You can still get a bank arrestment, but only for the debts belonging to the person who owns the account.
So, for example, if the account is in your name and your friend uses your account, it can be arrested for your debts, but not theirs. However, if their money is in your account when it is arrested, then in theory they could lose their money.
This is obviously not something you want, as they no doubt will expect you to repay them.
I would suggest it is not a good thing for people to use each other accounts for this reason. People sometimes say they cannot get an account of their own, but this is rarely the case.
Even people who are bankrupt can get their own bank accounts. The person using your account should get their own account, just even a basic account and this would solve the problem.
If there is anything else I can help with let me know.