you can't currently watch iPlayer abroad, and I think they've said that this will remain the case.
If you're paying for it, then that is going to be a very hard line to hold. I understand the issues (rights, in particular, mean that even if Mr Living in France wanted to pay, the BBC don't have the rights to broadcast some things in France, which is why Radio 5's streaming is geoip-locked to the UK, but there is an international stream that has had the sport removed) but in general it's been excused as being on the assumption most UK residents are covered by a license and those outside the UK aren't.
But OK, for "abroad" read "while on holiday in a caravan in Tenby, using the campsite's WiFi".
If they say the rule is 4 devices (say) then what would stop that being the rule?
It would be manifestly self-destructive. The BBC's fantasy is to shut down the UHF broadcast network, because the amount of money they are paying to Arqiva is beyond reason. The great thing about taking your TV over broadband is that you pay for the transmission, mostly: you pay BT / Virgin / Talk Talk / etc for broadband, and in turn they use some of the money you pay them to build the core infrastructure. The BBC just need a dirty great big pipe and, as I understand it, have been able to get the ISPs to pay even for that, because the quality of the iPlayer experience is a key differentiator between ISPs (Ie, if it turned out that new-ISP-X were cheap but iPlayer didn't work properly, who'd get their broadband from them?) So the last thing they want to do is give the impression that they are going to impose arbitrary restrictions on iPlayer-alike services, because that would just delay the day when they can turn off the transmitters.