Would never move the camper (other than to change sites at the same campground) without them in place and snugged up.
The Lippert slide I have uses a rack that moves on a nylon cog. The cog is suspended on a spring so that it will hop up and down when fully in or out so there is no damage to the slide mechanism when you bottom out. (You will hear a ratchetting sound at full travel.)
On a bumpy road, that rack is the ONLY thing holding that slide in. Even a one tooth hop will let rain in. Additionally, the slide is a "level floor" slide.
That means the slide is tilted out at the top "slightly" when fully retracted, just due to how the mechanism lifts the leading edge of the slide to bring it in. When you snug up the slide keeper bar, you can actually watch the upper corners seal as light sneaking past the seals goes out.
It is almost as bad on slides with hydraulics. A leaking piston will let the slide deploy as you drive down the road.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW