I think these guys are different enough, and relatively undocumented enough to start a thread with some observations.

I'll start with one that worried me, but I'm now putting down as normal behaviour.
1 - Staying submerged.
I've seen our checkereds in their water bowl, moving around submerged for maybe 20 seconds. I'm currently watching our female in her tub of water. Her body is completely submerged in a tub that is a little under half her body length long and half as wide again. She's laying motionless in the water fully submerged. I watched her for a while before thinking she'd drowned herself... It had been between 5 and 10 minutes with no movement, so I gave her a poke and she moved.
Since then I have timed a couple of spells where I can see her head is definitely submerged. First spell was 7m 48s before she casually stuck her nose up for 10s, then back down for 3m 38s, nose up for a few seconds, then back down for 3m 25s. She's now laying motionless in the water with her nose above the surface.
The water is at night time room temperature of 20.5 centigrade.

So my first conclusion, is that these guys need a lot of water in their permanent viv. This evening the female had spent a lot of time in the water, this latest observation is at 2:30am, after I decided to sleep on the sofa - the snakes are on a table in the living room until their viv arrives, and 20 minutes ago I woke up when the cat knocked something off the table. I'll sleep here tonight to deter him from investigating the new arrivals too closely.

Has anyone else seen this sort of submarine behaviour in other garters?