I suspect that if the use of Chuck E. Cheese tokens as a medium of exchange were to become widespread in a given locale (one with the profile of Las Vegas) the Secret Service would take a similar interest.

As it is, come on. Their budget is finite.

What about Ithica Hours? http://en.wikipedia.org/wiki/Ithaca_Hours

Looks like the test in question is metal coinage, which Ithaca Hours aren't.

Probably because they are only meant for use inside Chuck E. Cheese stores.