Foot strap contact.

Another one of the things that I "should know".
I recently replaced my non-adjustable stock Think strap with my own adjustable version. Once I have done that, I made it tight without much thinking. Next thing I know, I get into waves and go "whoa, I like it!".
Now, the confusion. Oscar says nothing about a tight strap and advices against pulling on it. He says both feet should push forward and one should rotate "forward" around the planted paddle. I am however finding that having firm contact between both feet and the plate helps with stability and rotation. In a way, it feels I can get my body where I want it to be more efficiently. This includes being more on-center and therefore more stable. And more solid connection with the boat which makes the whole system more stable (boat doesn't roll that far when it meets resistance my body almost right away).
And being able to get that non-pulling leg bent more and out of the way seems to help too.

My question is, is it a bad habit of some sort? It's confusing that Oscar is seemingly against it. 

I think of the footstrap as a safety belt for your foot, it keeps you foot in place when you are getting knocked around. Dont believe in actively pulling against it as it is countering your drive with the other leg against the same point. ie no net force addition. All forward force on your your drive leg should be countered/ braced against your paddle to effectively pry them apart and sent you forward.

Also the idea of maintaining say a 10%, or so, forward pressure on your non driving leg makes for a smoother transition to full forward drive when you put load on that side. Similar to the idea of not locking out your drive leg. That is increasing and reducing force while all the time keeping positive pressure is better than unloading and then loading, or even worse switching from negative loading to positive loading. 

Obviously thats an ideal and as you are alluding to in reality your foot will inadvertently unload at times in bumpy conditions. A more snug straps keeps that feeling of contact, even if its just psychological, it may provide confidence in your stability. It is possible that it may become a less than ideal habit though, like a training wheel. If it becomes the "norm" of your stroke technique it is taking away from the forward force differential between the paddle brace/drive leg.

The converse to that is more stability=more confidence in your forward stoke=more power going down....so swings and roundabouts

This brings about another aspect, if you are not supposed to pull back then is it better to train, in calmer conditions at least, with no footstrap to avoid the temptation to pull on it as part of your regular forward stroke technique?

I use my Epic V7 on lakes and rivers, I routinely use the foot strap almost like thigh straps to carve and maneuver the boat.  
Is this a bad habit?

It is confusing. I have been thinking about it and I doubt that constant pull is what I do. Up until recently my strap was extremely sloppy.
I think what's happening is better connection to the boat. Similar to using hip pads I guess. Another similarly here is with the advice Kenny Rice gave me which is to keep feet in a triangle with heels apart to increase stability. Tight straps feel very similar to that, just this reassuring firm connection at the feet that helps counter small side chop effectively.
Kenny's style feet is not always easy to maintain, heels slide in often and when you get a bump it's too late to angle them as the flow is already broken. Straps are always there and all I need to do is point toes towards me to minimize the side to side roll when cross chop hits. In complete flat none of that is neccessary, but it's reassuring to have the option to react quickly.
Anyways, this is my thinking at the moment.

Hmmm...
I disagree with the idea that you shouldn't pull back on the offside (recovery) leg.
Nelo, Elio, Vajda, Plastex, Think, etc, etc, all make "Pull-bars" for their K1s and some for Surf Skis.
I know a couple of former Olympic kayak gold medalists who paddle skis (quite successfully) and they both pull as well as push.
I think perhaps the point that Oscar was making is that your offside foot should never lose contact with the footplate.  If you have a loose strap, there's a strong likelihood that will occur as you pull. 
With a pull-bar, or a tight strap, the heal connection remains firm and the "pulling" is done by flexing the ankle to engage the top of the foot for the "pull".
Remember, the object of the exercise is to rotate your hips within the seat to gain maximum benefit from your leg-drive.
That's why K1 paddlers frequently use swivel seats.  It's also why the official ICF level 2/3 Sprint Kayak coaching manual specifies leg push and pull.

A snug footstrap is essential and really helps beginners (it did for me a couple of years ago) with stability and getting leg drive going. Its essential if you want to be able to throw the boat around a bit on some burly runs and waves.

I use the word snug since you still need to be able to get your feet out when that wave you thought won't catch you now throws a shadow over you. I've nearly broken a ankle by getting a foot stuck in a too tight strap. 

During today's practice I was paying close attention on how my feet interface with the strap. Having that 10% positive pressure on heel of the non-pushing leg feels pretty natural, but at the same time it's easy enough to keep good strap contact by holding the top of the foot slightly backwards so it stays firmly engaged with the strap. When the strap is snug I am not really disrupting anything by that.