Hi Acrbag, and welcome to FT!

I understand your feelings completely. I'm actually taking a friend to London with me next week, albeit he's in coach and I'm in business (I invited him after I already booked my ticket and upgraded to J, and there was coach saver available but not business saver.). My close friends know about my mileage and FlyerTalk hobby, and they understand where it comes from. They understand if I say, "I'm thinking of going to London or Hong Kong or wherever next month, and I could use some company while I was there. I'd love to take you with me if you're interested" that I mean exactly what I say, and they're usually ecstatic.

If you think the "freeness" of the offer is a problem, then you can suggest they paying a greater share of the hotel and food, etc costs at the destination.

Edit: Typo, and woohoo, 2000th post!