I am also having my wedding at an AI. This is how I see it- If your guest are going to pay to fly out there and also pay for rooms, then it's nice to choose a place that includes drinks and food. It's one less thing that they have to worry about, especially the alcohol which gets pretty expensive.
As for being worried about your guest paying for the wedding costs.
I have to pay a fee for the ceremony and reception dinner, but the dinner wasn't much. I figured that I would opt for a private reception dinner which cost more and either splurge on entertainment for the reception or provide an excursion for our guests.
In the end, the wedding itself is still expensive. I don't think your guest will feel like you are taking advantage of them or anything. If anything, they will see it as a fun mini vacation.
Just find ways to do little extras for your guest.