Backstory: I'm from the Boston area, as is my entire family and a chunk of FI's family. FI and the rest of his family is from Southern Connecticut. It's about a three hour drive.
Our reception venue does not have parking. Weird I know. Anyway, we're looking into different parking options. If people spend the night at the hotel, then we don't have to worry about it because the hotel is a block away. If they don't spend the night at the hotel, we are looking into different garages. The closest one costs $35 for the day, which is very expensive. There are other lots around the area which are cheaper that we're looking into.
FMIL is worried about the parking situation and mentioned that she and FFIL will be paying for their guests parking. I mentioned to FI later that I think if someone's parking is paid for, then everyone's parking should be paid for. The plan had been to offer parking at a lot somewhere we could afford it and maybe get a shuttle to take them to the reception. It's a work in progress. FI's parents would probably pay for a more expensive lot closer to the reception without the shuttle. FI thinks this would be fine as long as everyone is taken care of. I think we should treat all guests the same (as in paying for everyone's parking equally).
What's the etiquette for this? We have time to figure it out but FMIL is freaking out now so I want an answer the next time she corners me.