They are cheap and somewhat heavy. Perfect for my snakes.
However, I do have an idea for you - not sure if it would work. I give most of my snakes a (somewhat small) PVC pipe that they love to squeeze themselves into. Not only is it adorable behavior that I get to watch, but I think they spend a lot of time arranging and rearranging themselves inside it (or just sitting contentedly inside the tube). It is an easy way to give your snakes something they like to do, in case the tipping behavior is boredom. Just an idea!
I use those exact Ramekins too. No tipping since getting them in summer! Love it.