err we do this all the time at our parties.
Most of the time people keep using new cups/bowls is because they
leave it around, then not sure which one is their own, so safer to
get another new one.
Else, if you are using reasonably good quality plates, people won't
keep taking and taking new ones. Of course, they will switch if
taking savoury to sweet desserts etc, but not one after
another.
