Putting my subby 2-penn'orth in (or 2-cents, for my US friends!): I recently did this for the first time. What made me confident in him was that, well prior to the actual meeting, he gave me his full name, address and land/mobile numbers, which I was able to verify and publicise to my friends. So I knew he was not hiding and was being open and showing trust in me from the outset.
What Sir Russell says is probably true - I don't know if there is such a thing as Dom-bashing, but I guess there might be. Any stranger can be a complete wierdo. I hadn't thought of it that way - so, once again, thanks, Sir R, for your insight!