I find how some non-Shetlanders* refer to the outer isles irksome, for example, "I was on Yell" or worse still, "I'm going onto Yell".
Surely it's "I was in Yell" or, "I'm going into Yell".
My theory as to why this sounds wrong is that you go 'into' a community', but you go 'onto' an landmass. Yell is a community, ipso facto you go into it.
This theory is kinda backed up by the fact you go 'onto' the mainland, and the mainland is too big to be considered as a community in itself.
Or something along those lines....!
*IMHO, a Shetlander can be through birth or choice