I have never seen the like. Check out RG10, 147,44,19 1871 census for St Annes Westminster. Lots of people from all over the place, noted as strangers I think. The place seems to be called the Hotel Del Europe! Looks like dodgy doings to me.
It does appear in the papers from time to time, but the BNA is throwing a wobbly at the moment and it doesn't look as if it will be fixed until tomorrow. I suppose the 'guests' were all listed as strangers because no-one could spell their names
I have seen the term stranger used for what we might term as 'foreigners'. The dictionary give one meaning as:-
Perhaps it is a particular hotel for newly arrived persons from Europe or wherever to gather their wits & sort out where to go next.