For fighters, a lot of them do put out their best techniques - if not, you can surely see them in fight footage. What makes their techniques so effective tends to be their execution, not the technique itself. Can I do Cung Le's famous takedowns? Sure, if my opponent is just standing there cooperating with the fall. Can I do that in the ring like Cung. Not in my life.
As for forms, it's different. You do want to show off your skills in any public demonstration (otherwise, why bother?) and you want to look good. But there's no evidence, no body, nobody gets knocked out in forms, so you got to bust out your strong moves.
Anyway, that being said, there were modifications made to some of the internal stuff - particularly the iron body/iron palm methods - but the forms themselves are as ture to what Wing Lam was teaching at the time as we could make them. There are a few errors here and there, since we cranked'em out pretty fast (at least one a week, once one was shot, scripted, edited and narrated in a single day). So the few of us (well, four or five people) who worked on those videos might be able to tell a video student from those errors, but that wasn't intentional. I wish I could say we planned that.