While the seal failure rarely leads to a bad situation if you catch it soon enough, I posted my experience with the leaking seal where the bearings were pitting on one side of the roller. Turns out the retainer nut was not square when it was machined and was the cause of both the seal and bearing failure. I had never seen that happen and it certainly came from Rockwell like that, so paying attention to even a trivial job like changing out a wheel seal is worth the effort.

You can't just walk away and not ask, "I wonder why that failed?" especially when it fails prematurely.