Oh the horror! Zero G, and floating her teddy bear around the cockpit was an indispensibe trick to keeing my then 5 year old from getting bored during a flight home.
I am aware of many dumber things being done in planes than letting a Coke can loose during zero G flight.
I did the -1 G flight testing of the DA-42-360, as it was a certification requirement for the engine STC. The engines did cough a bit, but sprang back to life immediately upon restoration of G. We did throw out some engine oil each time, and the observers on the ground reported seening the cloud of oil mist. But, that was -1 G, when anything loose is pinned to the ceiling.
Zero G is a non-event as long as it is planned, the area of flight is appropriate, the cabin is secure, and occupants willing.
I'm sure there have been many more articles fouled in the nether regions of a cockpit from simple poor housekeeping while flying, than from planned zero G flight!