This is a sort of follow-up to Is there expertise in philosopy? The Barefoot Bum linked to something I had written on the subject, as well as linking Stephen Law and adding his own commentary.
I don't have a lot to say about this, but I do have disconnected points:
1) When it comes to listening to experts on an empirical subject, what you're doing is broadly similar to trusting the testimony of someone on a more straightforward manner (what did you do last weekend? etc.) It's not obviously problematic.
2) You have to look at the biases of the people involved. Law brings up Biblical scholarship, a case where almost everyone goes into the field a believer and for religious reasons, an obvious case of this.
3) There is a distinction between "philosophers believe this, therefore it's true" and "philosophers believe this, therefore it's reasonable." I've heard the things along the lines of the former from William Lane Craig, but never from an actual philosopher. The latter is what you're likely to hear from an actual philosopher. I tend to disagree, but it's still a distinct claim.