I've never had any issues with my t's and uneaten roaches, but I feed almost all of my t's with tongs even my 6''+ P. Regalis females. Sometimes they'll bury themselves in the substrate and will come out and get eaten when the lights go out. I've fed a t a roach before then molted the same night and didn't have any problems with the roach bothering her. I've been raising dubia's for over a year now and would never go back to feeding crickets, one adult dubia is equal to about 10 crickets and they don't stink which is a huge plus.