I don't want to cause offence. But I don't know sometimes in a bar, when going to the restroom, to take my bag or not. Potentially someone could steal it and the bar may not have cctv. But then it may cause unescarrily offence I guess to take my bag.
Take your bag with you, I would say. If you don't have friends there with you and they can watch it. Leaving something alone in a bar is a great way to lose it.