seems no problem
Thanks for your replies everyone. After I posted we lost internet service so I haven't been able to respond. We have a Keystone Hideout 38FQDS. By permanently installed, I meant that we had it set up on blocks by the dealer in a seasonal park and that we will not be moving it. There are two slides on it.
"Cool Canuck" I hope that wasn't in our trailer park! That would be a nightmare. But really that's what it felt like. Or like a huge bear jumped out of a tree and landed on our roof (that's a possibility). We did check around the trailer with a flashlight after it happened (no Buicks or golf cart roofs!) and it was still firmly planted on its blocks. I emailed the dealer and they were going to be servicing some trailers in the area during the week--and we were already scheduled for some minor repairs--so they stopped by to check it out and looked under the slides, examined all the blocks etc. and said everything looked fine. The one thing they didn't do though was to run the slides in and out!
SAABDOCTOR and Halibutman214, I wish I'd seen your recommendation to check if the slides still move in and out okay because I would have asked the service guy to do that. I did think of it after the incident but didn't want to risk putting them in and then not getting them back out again since we were having visitors come up the next day, then when the service guy came he didn't do it and I didn't think to mention it (again I guess subconsciously not wanting to ruin our holiday), but if I'd seen your comments I think I wouldn't have been so silly. We left them out when we left but when we return we'll try them and hope for the best.