I think you will find that most people come to the US to complete the JAR PPL as quickly as possible - not to half do it and then go back home to finish it.
Understood. I was also under the impression that quite a lot of Brits book three weeks' leave from work, try to do the "CAA PPL in 21 days" and fail, which might give rise to the same situation.
Remember , there is plenty of paperwork and cost involved in getting to the US for flight training. Not least getting the visa, going to London for the interview etc.
Sure. I've done the sums, and with £/$ the way it is, break-even is still around 20 hours - which I'll achieve in less than two weeks, as opposed to probably 3-4 months of weekend sessions in this country.