Yes, three times I have approached a wg on AW and been refused:
Once because I said I wanted DFK, and she was only prepared to offer a half inch of tongue between clenched lips
Once because she said I was too old (apparently she had a 50 limit)
Once for no stated reason (although I suspect age again)
I must confess that I have several times wondered whether, if we can satisfactorily identify a wg, we can summon her before the Equal Opportunities Tribunal and ask for compensation for hurt feelings when we are refused on either age or racial grounds.