Go on YouTube and check out the damage that can occur with old dry rotted tires - when a dry rotted tire throws a sidewall or ply separation, it explodes, it doesn't go down easy at all. That explosion will ruin so much stuff on your car it isn't funny. Check it out:

Tire Explosion

This does happen on street cars too -- just because it's on a rolling dyno isn't the only reason this did this. Look at how thick the sheetmetal is in the trunk area that is mangled -- not worth it in my book.

Tires are cheap -- bodywork and lives are much more valuable. Yes, stop being cheap................