mooredog,
Very strange...Years ago when dealing in Las Vegas (low limit) we were allowed to tip cocktail waitresses and were also allowed to remove small denominations from our stack for keno and even small purchases from the gift shop, gum or candy etc. Your situation is quite different and I'm sure you could put a house rule in effect that might allow a small percentage to be removed from a table stake in a situation like that...interesting.
i.e.House Rule #121 Violation of Table Stakes: Once a hand begins, no player involved in further betting, may remove more than 5% of his table stake prior to completion of the hand in progress This will apply for tipping or any
other unauthorized purchase. Or something to that affect.