It's a major issue. If you break one of the steel cords, you increase your chance of seperation greatly. Typically, a puncture only seperates the steel cords, going between them. If you drill it with a power tool, you run the risk of actually cutting the cords. Reaming with a hand tool is not near as damaging. You might do a little damage to the cables, but they won't seperate any time soon, if it's a quality tire, which is hard to find these days. On a bias ply tire, reaming is not a good idea if it can be avoided. The nylon cords can easily be cut. I personally, don't like plugs, and prefer patches and boots, similar to show above, but then, I also have to stand behind my work, as MWilson said. Doing it almost every day, I can dismount, patch, and remount a tire just as fast as most people can install a plug. But I'm set up to do it, too. Also, from experience, I'd say the rubber cement, (only named such, as it's truly a vulcanizing, chemically bonding cement, much like PVC glue on pipe) has a lot to do with a tire staying together. Whenever that steel cord is loosened from the rubber, it leaves room for it move in the rubber, allowing dirt, water, air to get in there and work when the tire is flexing from it's radial movement. The bonding from the rubber cement causes it to rebond, essentially sealing it off. The wire guided boot patch I showed above are for large punctures, and when using the rubber cement, they glide easily into place, as the cement softens the surrounding rubber until it hardens, acting as a lube, essentially. Then the patch is bonded to the surrounding hole, and there are no gaps anywhere, even if the cement fails. The patch wears down as the tire does, and no dirt or moisture can get in. The patches compound is actually pretty soft. And, as a "specially trained tire professional" we always grind on the area to be patched, to remove any uneven places, and then use a specific rubber cleaning chemical to help remove any mold release agents that may be in the tire, which would keep the cement from bonding with the rubber. And, as labeled, NO SMOKING while patching tires!!! That stuff'll light from 3 ft away!!!! :-laf