If I remember correctly, accommodation for officials is provided by British Swimming but on a shared twin room basis. You can, in special circumstances, book your own room but you can only claim 50% of the cost. You get a meals allowance too and you can claim travel expenses.
I know many adults without swimmers who give up a lot of their own time to volunteer as officials, including at Commonwealth Games level. None of them have ever gone wandering around in the changing rooms though.