Sorry to labour the point, chiglet, but I don't think that is entirely right, and this is the big difference with policy in the UK, and the reason for this thread. (I am only talking here about traffic INBOUND to the UK.)
If someone abroad files into his grass strip in the UK, and nominates his mate Bob as his 'Responsible Person' and tells him he is coming then the 'parent unit' is not involved. Do they indeed get the FPL?. The aircraft arrives safely, meets Bob, and they go down the pub. There is no requirement to close the FPL - there is no concept of this in the UK.
If Bob is on holiday so that thre is no one else to nominate as a 'Responsible Person' then the pilot rings his parent unit (or, I think, he can nominate any other unit) and says 'I am going arrive at Lower Snodgrass at time xxxx.' It is then incumbent upon him to ring his parent unit after landing to 'close his FPL' otherwise SAR springs into action and mountain rescue goats are mobilised, after the required time intervals. This is the only time in the UK a pilot is required to close his FPL.
The system in the UK isn't less safe than others, just different, It's a pity we are different as it would make life easy if we were all the same but it is just the way things have evolved I guess. There are a lot less 'wilderness areas' in the UK.
Departing traffic is different, and pilots need to understand if they don't get a departure time into the system, some how, then their SAR insurance isn't activated.