Can anyone point me towards some tech data or references regarding leaving a gap between landing gear chocks and the tires? (bonus picture in this post to keep it from being boring)

Ground-handling guy here. Have recently run into a common-sense detour on this and was told a gap between chocks and the tire is unacceptable. Having seen plenty of trapped chocks before, this bothers me. I thought I remembered something in a 737 training manual that said it should be a 2" gap if not parked on a slope and <35knot winds, but I can't seem to find it. I've been asking around and everyone kinda says, "Duh, leave a gap..." but I can't find anything official. Anyone got anything official they can point me towards? Adding a cool picture to spice the post up. It's a C-130 that had hot brakes in Kandahar back in the day and the tires caught on fire. https://preview.redd.it/9utlwayj232g1.jpg?width=4000&format=pjpg&auto=webp&s=c412056a2124cdabedcab665a0d1eb11d237f5db