If you look at how they operate, they actually couldn't seal flush. The hydraulic slides have a surface seal on exterior that the slide flange compresses onto, and it can't compress it flush. Water rolls right off the seal and down the side.
The schwintek at the bedroom is a bit different. Mine sticks out a little further than the hydraulic slides because they changed the seal design somewhat to allow for the motors to be accessed on the inside instead of through the outside trim. That one you have to be careful it closes all the way (at least to where the seal compresses) because they will stop short with a low battery or if they get sticky.
We looked at a Cardinal years ago that had a flush slide, but the seals were all exposed. I would not consider the Cardinal top end, so I would agree with Vic.
Brad & Dory - Lone Tree, CO
CURRENT - 2013 Itasca Meridian 42E/2013 Wrangler 4dr Sahara
SOLD - 2014 Redwood 36RL/2014 F350 DRW