[Bruno]

Wait unambiguously allows the character to Attack and Step Back - or Step Back and Attack, but either way he only gets to start his movement once the wait is triggered. He can also step sideways, jump up on a soap box (usually counts as a step as does jumping on/over other low obstacles), and various other Step-equivalent things.

The problem with the Waiter scurrying away "indefinitely" is that this scenario requires an infinite featureless plain and an attacker who mindlessly tries to follow you. It might work the first one or two times, but after that the attacker is going to stop dutifully stepping forward so you can try to hit him again. Well, unless he's an idiot - you can probably get a zombie to chase you forever.

This isn't meta-game knowledge the attacker is acting on, once it's done a few times - the Waiter has demonstrated his strategy quite clearly, his cards are all on the table, his Maneuvers speak louder than his players words, however you like to phrase it.

Committed-Attack Long, a lunge, extra-effort for an extra Step, all out attack, Slam, flying tackles, Move and Attack... or just make Defensive Attacks while herding the Waiter into a corner or against a table, onto bad ground, off a cliff, or into your allies. And the Waiter will be useless at holding an entry point or holding his place on a line of battle, allowing foes to break the line and attack his allies from the sides or the back.

I say don't forbid it - it's a good tactic but not a game-winning Always The Best tactic, and it's sometimes a really terrible tactic. Allowing it results in a much livelier, more dynamic battlefield, where you have interesting choices to make that sometimes will be good, sometimes be great, and sometimes be stupid.