Colin Wilson wrote in message et...
Are there any practical reasons why wiring should not be run behind
skirting boards?

Nails.

Ah...
Fortunately I don't plan on hanging pictures on the skirting board and
don't know anyone who does.
The skirting board would be ply, fixed to top and bottom battens and
moulding on the top (IOW no reason to put nails where the wires are).
Cheers, Mark