Positive anecdotes are often presented as proof of the standard, when they are actually the exception to the standard. That's the primary thing I try to get across. There's risk in using the brand for service of a vintage watch, but if people want to take that risk, as long as they know the risk going in then the result is on them.
I would be the first to praise the brands if they actually respected the vintage nature of the watches that were sent to them, but generally they do not. Even when there are clearly ways to preserve the parts if they are too risky to keep on the watch as they are, their only option is to replace them with new parts (or as in one case here, tell people that the warranty is void if those parts cause a problem - a cop out solution IMO).
No one is suggesting leaving parts on the watch that are going to cause a warranty issue, as every watchmaker wants to avoid that, myself included. It's the solutions presented by the brands that are problematic.
Cheers, Al