Edit: I just heard a pilot talking about a stuck mic - problem solved, maybe?
I once witnessed a similar problem in Sao Paulo Int'l - Guarulhos (SBGR/GRU). A VASP plane, which was performing an engine test in a remote are of the airport blocked the ground channel for some 20+ minutes. The ground frequency was changed to a spare channel during this period but didn't avoid the ground controllers and other pilots to get pi*** off and complain about the careless mechanic who didn't notice the mess he caused.
Cheers all,
Ricardo
SBFI