Is a "Plug" repair or "liquid sealant" an acceptable repair?

Got a reply to a post on an RV Forum on a discussion on the use of a "plug only" type repair. I had posted a couple of pictures of examples of tires that had been run when significantly under-inflated and the owner only used a "plug-only" type repair.
Here is a picture of a tire showing the cracks through the inner liner due to the tire being run severely under-inflated because of the air leak, and run for hundreds of miles.

Here is another tire that had significant damage from the puncturing object but the damage went undetected because the tire was not dis-mounted and inspected.

Here is an example of a tire that was "plugged" 3 times but apparently continued to leak and the owner put some type of liquid sealant into the tire trying to stop the leak. (Note I don't think this is Fix-A-Flat brand sealant but you understand what I am talking about here.

Would you feel comfortable driving on either of these tires?
These examples show why the proper method of repair is to Dismount, Inspect then if the tire is OK a patch and plug and be used to seal the air chamber and to protect the steel belts from rusting due to water entering the belts from the outside. If you don't inspect how would you ever know the extent of the damage that has been done to your tires?

The person was asking the initial question about the advisability of using a plug, I assume wanted to do plug repairs continued:

"I'm still not sure what point you are making, especially if the cracks and the puncture are unrelated.
If the plug repair was successful, as most are, OR if there had never been a puncture anyway, then a tire interior would never be inspected and so cracks caused by say, running over a curb or large rock, would never be noticed unless they caused air loss that resulted in testing or inspection.

Your second exhibit shows a tire with a plug repair that we don't know if successful or not and again, probably or possibly unrelated damage that could have been there for hours or years and may or may not have been the reason for the tire being dismounted, so again, your point? Tires get damaged, tires fail and as your photos clearly show, a simple sharp object penetration isn't the most serious injury tires are subjected to."

I agree it may be "possible" to do a "plug" repair that will allow a tire to hold air. The main problem is that most people who do a plug repair as a "temporary fix" to allow them to stop the leak, re-inflate the tire and continue to travel to get off the highway. Most will never go the next step to have the interior of the tire inspected.

Innerliner cracks come from operating a tire for many hundreds of miles with the excess deflection that is probably due to running significantly underinflated. Such operation can not only damage the inner liner but also compromise the belt integrity.

Many times if there is a belt separation later, the owner does not associate the decision to not have the tire inspected and replaced if the damage is discovered so simply blames the tire MFG for the failure.

The second picture shows the damage to the interior of the tire when the object (maybe a piece of wire) was left in the tire and it cut through the inner liner. This will result in high-pressure air being forced into the body of the tire and again possibly leading to a separation that again the owner does not associate with the puncture weeks or months previous.

Some points to consider:

1. The use of a plug only will void any tire warranty according to most tire companies (GY, MI, BS, etc)

2. The use of a plug only is specifically not approved by DOT so don't try and make a claim of a tire being "defective" to NHTSA or in any court of law

3. Unless you have personally inspected a few thousand tires and can provide evidence that tires with improper repairs do not suffer secondary catastrophic failures, I suggest you include a warning with your posts that your observations are only based on your experiences with a few tires.

I agree that we are all entitled to our personal opinion but not our own facts, especially when others may be relying on our statements for the safe operation of their vehicles and specifically their tires.

Go ahead and use a plug if the situation warrants but just be sure you have the tire dismounted, completely inspect and if possible properly repaired but please be clear that without a complete inspection it is possible that the tire has suffered irreparable damage and should be removed from service.