We have run into the size issue in the past at a Texas State Park. had a reservation and get there and no site is big enough for our rig. Rig size was noted on the reservation, yet, the sites were taken on a first come basis. The larger sites were occupied by pop ups and tent campers. We had to go else where for a site, but after some fussing, we got a refund.
Why ask about rig size when they do not hold a site for a larger rig. Now Texas is moving to site specific reservations. This is not good as you find a site for a day or two and then you have to move. You cannot find a site open for a week to save your life.
It is getting so hard to get sites unless you book at least 6 months out, we are considering coming off the road and parking the rig. Too many people reserve and never show up and the site is wasted. As park volunteers, we have seen people turned away as all of the sites are reserved and the next morning, there are several vacant site due to no shows. The parks need to make a larger fee for a no show that does not cancel...like $50 to $100 for a no show.
Ken