I'm pretty sure the level of RF in a model plane is unlikely to approach that needed to produce arcs as it's receiving, not transmitting. OTOH long conductors can also look like multiwavelength antenna elements, absorbing RF and storing it temporarily assuming just the right lengths, and if their length changes at just the wrong time that energy will dump out as sparks, producing interference with desired operation. But this smells improbable; one would have to work at it.
The situation with phones etc is the opposite; engineers stay up late making sure this kind of thing can't happen.
This sounds like a more reasonable concern, especially as the metals' work functions may be different allowing rectification. This applies even if the metals are the same as one bit may be more or less oxidized than the other.
A somewhat less catastrophic version of the first idea seems more reasonable; that the moving connected metal parts will look like a variable antenna element parasitic to the actual antenna on the receiver, reducing/reinforcing the field strength seen by the receiving antenna making reception vary wildly as if the plane were jumping large fractions of a mile from the transmitter as the parts move.
Mark L. Fergerson