No, not personally. I am not sure I've even ever seen them myself, they don't mix with the locals...
It's possible I saw them when they set up their gallery in the village (which has changed into a different shop now) but at that time, I did not really know what either of them looked like. Only this year I know, since I read/heard about all the goings on at the hotel and saw them posing in lots of photos online. I'd recognize them now if I passed them in the street.
The hotel itself I often go right up to, sometimes walk right through its grounds, because it stands on the cliff and anyone can walk about on the cliffs. When I first moved here, my bf suggested we check out the hotel coffee - I'm glad we didn't. >_> Even so, I've still never seen them.
The closest I've come to being anywhere near the Mappins is seeing their flash car parked up in the grounds of the hotel when I pass it. If they do come and go from the place in it, it must be in the dead of night or something, because I never see them driving it.
My bf has met some of their staff... he used to work in a local store, and he's served some of the (Polish?) cooks they employ. He says they don't say much, they buy cans of beer and go back to the hotel. They don't go into any of the local pubs or talk to the locals. His boss in the store told him that they are always like that. He also heard that the cook guys have been there a few years, but that other staff have been treated 'pretty badly' by the hotel.