Are cooling mats safe to leave with my dog unsupervised?

High-trust community threads on r/dogs urge caution: don't leave a gel mat with a chewer (the gel is generally non-toxic but can cause GI upset), and don't put one in a crate where the dog can't move off it if they get too cold or the mat heats up in direct sun. Supervised use on tile or in a shaded spot is the consensus safe pattern.