Solution one;
I found these gel "stickers" that I just put around the viv. about 5 inches up, this means that the crickets get stuck to this and can be easily picked off by a hungry dragon. No "gel" comes off, and they or human can easily peel the crickets off but the crickets themselves can't pull themselves out. Hard to explain.
They don't leave a mark when you take them off the walls. They're non toxic, 100% natural, hard to get though.
Solution two;
Double sided sticky tape, stick this around the walls of viv, at a low height so easy picking for you and or dragons, and once finished with easily peeled off.
Cheap and easy to find. Best one.
Sounds like the melamine has some texture. You'd have to take your beardie out, but I think you could sand the melamine with some fine sandpaper and smooth out out to the point the crix could no longer climb. But that's just a guess on my part.
What I did was cover the walls with shelving paper (most hardware stores stock it - it's self adhesive decorative paper) and now not only can the crix not escape but it looks great as well! :lol: