Trailer tongue failure

A little afterthought concerning trailer tongue failures. I have a
3/4 ton GMC pickup with a factory installed hitch. Last year I towed
my glider 700 miles to do some repairs. When I got to my destination
and went to unhitch the trailer I found the trailer tongue a few
inches from the ground. My 10,000lb hitch had broken two of the four
mounting ears where it bolts to the frame and the other two were very
near breaking. The entire hitch was dangling loosely and I'm sure
very near breaking free entirely. I have witnesses. Since the safety
chains were attatched to the hitch they would have been worthless. I
was very close to serious property damage and possibly much worse.
Hitches are not bulletproof. I do tow a 4000lb travel trailer
occasionally. The hitch shop that replaced the hitch said this was
not an uncommon failure. I would recommend inspecting the hitch
itself, especially the mounts for cracks and security.