Sarah, I think I read somewhere that cot bumpers arent recommended for babies under 12 months. I was thinking of getting some as well, but I am still not so sure. Claire moves around lots and often hits her head too and starts crying. I never thought of them as being heat trapping (its not that hot here) but now that you say that, I can see how it might be an issue in a hotter envoronment like Townsville. Hope Ari settles down and its just teething that is bothering her.