Yes monkey i thinK it varies - some 1st yr flat shares bond for ever, others have fallen out by mid 2nd term and none of them ever speak again after june that year! (Exaggeration).
I do think it varies according to course how much it will matter To the students - where its a very vocational degree, at least some students, particularly mature students, will be not that bothered about friendships.
And (speculation) some courses are more linked to friendships than others eg my impression is that lots of medics team up as friends, as do the vets, dentists etc (purely impressionistic though!).
assuming the universities arent expecting current students to break existing tenancy agreements starting this summer, the bubbles are going to be of limited effect if those students come into contact with 1st yrs on campus. I suppose it is about limiting rather than eliminating risk.
I think ‘only a yr’ may not convince all 18 yr olds - life is so much less predictable than it seemed to be at the beginning of this year, they may take the view that anything is now possible! How that plays into Their decision making Is less clear...