PCM, Although it uses the same 72MHZ frequency, can give you as much as 3db processor gain which is the same as doubling the transmitter power. Its not a cure all but it can make hell of a difference.
In spread spectrum Technology I have seen as much as 40db processor gain claimed although I find it hard to believe.
Your SS 2.4 system spreads its data over a 1 mz band(4mhz with FSST systems) according to a pseudo random key(sequence) developed within your system. TO interfere with your rf the interference needs that key. The chances of that are virtually nil.
40 db is four orders of magnitude. There has to be a lot of power in that spark to swamp the receiver.
The other servos are working. Does that not give you a clue that the receiver is still working?
You guys can continue to punish yourself with obsolete rules if you like. Have at it.