Just for the record, I'm an OTR trucker and a squonker will drain the entire bottle of juice up through the atomizer going over mountains out west. It's not quite as bad if you're using it, of course, but crossing the Rockies anywhere in Colorado you can't vape as fast as the liquid comes up. I make sure all of my regulated squonkers are drained before I head out that way.
Weird, 'cause I've never had that problem flying, where the pressure altitude goes from 0 to 8000' (and of course back down again) much more rapidly than it possibly could driving, and I've had a squonker in my shirt pocket on every flight I've taken in the last ~4 years.
OTOH, I always had trouble with tanks just driving the Appalachians on the east coast (3000' max).
juice comes out through the atty due to changes in air pressure, which causes air in the bottle to expand.
and since the only outlet to vent is in the atty, juice gets pushed up as the tube is submerged in liquid.
filling the bottle as full as possible will help as there is less air to expand
or having the mod upside down will help as only air get "vented" out, but juice in the tube will get pushed out and juice in the atty will follow gravity
tanks also face this same problem with air,
but iirc different pressure also affects how tightly packed the cotton needs to be before leaking occurs, so a fully filled tank might or might not still leak (can't remember if higher pressure needs more cotton or lower pressure needs more)