Ex-EU fares seem to be getting more and more publicity, and if an increasing number of people drop the final segment BA may start to impose restrictions from not allowing short checked luggage, asking for the fare difference for no-shows, or removing avios/TP's for all segments. The US airlines are much stricter on hidden city ticketing, it is only a matter of time before BA follows suit..
I think from our perspective here they have been getting more popular, though they've always featured heavily in magazines such as Business Traveller for as long as I can remember (tips from the pros!) I can't see BA doing too much before killing the very type of client they want to attract.