my experience
I've been playing about 5 years. I've been 86's twice, neither for counting. One for just winning. One because someone bet on my circle (bet _big_ in a big count) and convinced the pit we were a team by doing so even though I had never seen the person before.
Back-offs are a different matter. I was backed off more in my first 3 years of play than in the last 2 by a _huge_ margin. My first three years were a learning experience, where my wife and I would check into a casino and I would do 90% of my playing where we were staying, for the comps more than anything. I played 2-3-4, even up to 6-8 hour sessions back then, and even though I was betting a max of $100 on shoe games (spreading 5-100 or 10-100 or maybe a little more) I was simply playing too long. Give the pit enough time to watch, and it will eventually catch up. For the past two years, I have completely changed my playing approach. I still count just the same, I don't do much cover betting unless the pit is at the table watching (I am a bit more careful during those times) and I don't play more than an hour, ever, except for _rare_ occasions. As a result, my back-offs have dropped to near nothing for the past two years, since I have been carefully following my hit-and-run type playing. I'm not a big player, obviously, but betting red for hours will eventually result in a blip on someone's radar, from experience. Moving around a lot is much more effective. The down-side is comps as you end up with small comp credits scattered all over, rather than everything at one place.