I don't think its rude to ask at all. We are paying for the wedding ourselves. I got my FI to ask his parents when we were early on in the planning stages. They helped us out when we bought our house together so we weren't sure if they were going to contribute anything for our wedding. My FI just straight out asked them, he told them we were planning our budget and asked if they were thinking about contributing anything or paying for anything as a gift. They told us that they weren't planning on contributing anything at that time. My FMIL has changed her mind very recently and told us she will pay for a traditional Chinese reception for when we get back (my FI is part Chinese) so we don't offend that part of the family who's not invited to Costa Rica or she will give us the amount of money that would have gone to the reception to put towards the wedding (and have those people not invited will never speak to us again!) We were surprised that she came up with this, now at least we know where we stand when it comes to budgeting. It can't hurt to ask, your FI parents. You might be pleasantly surprised!