"If I have understood you correctly you are of the opinion that I can dance on whatever set of beats that I like."
That's overstating it a bit, in that most wouldn't take arbitrary leeway, but it is ultimately true.
You can do whatever you want, provided that you KNOW what character will result from your decision, and that you have CHOSEN that character to SKILLFULLY build part of a greater whole.
This is very different from placing something arbitrarily or carelessly against the music because you either don't know that you are doing it or don't care what will happen as a result.
Ultimatly, it's only "wrong" if you can't "sell" it as part of an overall idea. Even if it's technically "right" in that each individual detail comes literally from the book, it can still be "wrong" if the overall effect is not convincing.
To address that little example, no, we wouldn't generally put the 2nd step of a waltz figure on the first beat. But there are a number of situations where we would put what is ordinarily the first step of a figure at a later point in the music than usual, because we've put another step in front of it. The result isn't simply the ordinary figure displaced, but something new.