In America, it's common to ring the bell for a good tip.
In the UK, we ring it once for last orders, to warn people they only have ten-twenty minutes (depending on the bar) to get more drinks in. Then, we ring it a second time to let everyone know the bar is closed. Some places ring it again when the drinking up time is finished, but most don't...
when you come to Bermuda...when you sit at the bar and dare to ring that bell - you buy everyone who is sitting at the bar a drink...hope your pockets or wallets are full!!!