I assume he will lose the accommodation he chose at the point of changing his allocation. That TSR article suggests it’s pretty easy to change within 14 days of selecting.
Is he essentially trying to hedge his bets? Ie wants the accommodation of choice at a uni that might not be too choice, but retaining the opportunity to switch his top choice and presumably get top choice of accommodation there too?
It is annoying that some unis do accommodation as first come, first served. It’s especially annoying when the equal consideration deadline was only yesterday and some universities have made very few offers as yet. I imagine it’s actually private halls which are open this early and taking bookings (does it involve a deposit too?) but others like Nottingham and York also do it for uni owned accommodation in a few weeks, for those who firm them, whilst many will be waiting for other more prestigious places to offer. It’s an attempt to pressure people to firm them before they have another maybe preferred option, with the threat of less access to the best or most popular accommodation. Reminds me of the phase of unconditional offers too, which often persuaded students to not aspire to their top choice but go for the certain, easier option. That’s not to say Nottingham and York aren’t good options - they really are - but they know where they are positioned and that they are not the top of the RG and a good number of applicants might insure them or turn them down and they are trying to convert those applicants into firms instead.
OP is it private halls you’re talking about? If it’s uni accommodation, which are issuing their accommodation already, or is DC just getting ahead ready for that?