Here in Oz, any plug type repair done from outside the tire is considered temporary & is technically 'only legal' in order to get you to a place of repair (the nearest being implied, but not spelled out!

); and there are fairly specific directions on what type of puncture can be permanently repaired & where any punctures that are going to be permanently repaired can be located on the tire too. :lecturef_smilie:
In brief, here in Oz all punctures that are allowed to be repaired 'permanently'
must be repaired from the inside of the tire; any sidewall puncture that's allowed to be repaired (& not all are!)
must be repaired with a patch or gaiter; all tread repairs
must use a mushroom type plug &/or fillers and a patch or gaiter; and there's a bunch more specific stuff detailed in the
Tyre & Rim Association of Australia's Yearbook, their Annually issued Manual, which is based upon the
Internationally Agreed Tire & Rim Standards, of which I believe the USA is also a signatory, so I'd expect
the requirements to be fairly similar, even if the Federal Legislation backing the upholding of it's strictures & their enforcement isn't.
But as others have said, your vehicles tires are the only things keeping you safely on the road, so you really hafta
think about your safety & the safety of those travelling with you & around you! :thumbup: