Withdrawals?

Hey guys, I’m from the UK and I’ve been shortlisted which I’m so happy about! But i’m just wondering, once getting the placement, what if I don’t like the placement and decide to withdraw? I read online that they kinda expect withdrawals when people don’t get their chosen placement. What’s the consequences here if you withdraw straight away? And not getting any fines? Would i be banned from applying again?

Thanks for the help!