Ok, just one example.
Unless each character is checked thoroughly (and that, if I understand you right, is what should not be necessary), you can lower the cost of all your abilities to a miniscule fraction of its real cost by inventing and applying all sorts of situational disadvantages, that will simply never come into play.
Now that's just a stupid example off the top of my head, of course.
For a tournament, some sort of balance is necessary, unless it's a character creation (munchkinizing) tournament.
Simply removing the stopsign powers doesn't do that in the slightest.
Bye
Thanee