Rogue

I think the primary concern, as always, would be safety. With a wired system you know who is holding the control. With a basic RF circuit, there is always a risk of interference that could either (i) prevent the signal triggering the remote unit or, more worryingly (ii) trigger the remote unit without you intending it.

There are RF circuits that should help reduce some of the concerns through pairing. I would imagine that you could start from some RF encoder/decoder pairs such as the RF600, from Maplins or Rapid Electronics. Beyond my current skill to say how you would build up a suitable circuit from here, but maybe a starting point for research?

Would it be feasable to lay out wiring to some key junction points on a permanent basis? Then the devices could be connected to these as required, limiting your setting up to a few meters of wiring per device each time? May end up a bit safer and more reliable as well.