I don't mention it verbally, but its definitely on my dating profile. Seriously haven't had any issues with it, most people don't care and those that do are....eh lame. I've had a few dates were I was tired/stressed and my stutter was severe but those still ended up well. I don't think you're entirely wrong, if they don't know what it is I can see them mistaking it as a confidence thing. Maybe in the middle of a stutter pause smile and say "I have a speech impediment", I've done that a few times.