Several years ago both bolts broke on one of my TT's. It happened on the car deck of a ferry during the evening commute. Both bolts had loosened and backed out. I had checked the bolts 5 or 6 months before they snapped and only one had loosened a little bit, (1/4 to 1/2 turn).
The stock bolts are 5/16" coarse thread. Other ferry riders found the two snapped bolt heads but I can't remember if they were marked or not. After getting the bike home I turned out what was left with vise grips.
There is lots of material around the side stand bolt holes. Decided to up-size the side stand bolts to 3/8". Drilling out the holes is pretty easy as the tap drill, (5/16") just tracks and follows the existing hole.
After drilling I cleaned the holes and bolt threads with brake cleaner then assembled with Red Loctite.