Most ESCs should be tolerant of the occasional momentary loss of signal. If the switch is a microswitch, it should hop from one state to the other before the PIC gets stroppy, as a side effect of the PIC programming needing more than one frame to fully settle on a new value. Each data frame is about 20mS long, each channel uses about 2mS, the microswitch will change state in about 1 mS - the PIC will at worse get one mangled frame, a frame a couple of mS early or late, of a missed frame. If the ESC is programmed for the real world, it must tolerate these conditions, or gather a lot of complaints.
MicroSwitches got the name not from the size, because most are big for the current handling, but from the shortness of the switching time.