As far as i know it is very lax. I think if you told the owner of the garage he might let you park there a while
If you have a trailer or extended Van then easily overnight. It is a rest stop after all, which means that you can get some shut eye if needed but not prolonged stays. Safety is the concern to all drivers, if you need to rest for a night, i don't think the management would have a problem.
Thanks! Your answer is awaiting moderation.