I've seen dozens and dozens of posts over the years from people who have a lab supply a profile only for soft proofing and not for final output. They are told they can soft proof but can only use the profile for that use, data must be sent in sRGB. Here's one example from a pretty big lab:
Wow, Andrew, I stand corrected. I have visited the whcc website within the last couple of years and never saw any policy like this. Thiings appear to have changed dramatically in recent years. So, perhaps this "soft proof only" policy is a newer trend, but nonetheless a particularly disturbing one. Indeed, this entire thread just convinces me that printing my own work on my own printers in house makes far more sense than trying to develop a good long term relationship with an outside lab. The traditional photographic print is under siege from a lot of different technological innovations these days, but print providers shouldn't be stepping all over themselves to be killing off their own customer base.
thanks for the heads up.