Here's a fun quote from the Exjw Reddit thread about this:
I've actually taken the "Woman and Her Offspring" tour that this group offers. I have to say that the pioneers that give the tours have a sweet gig. While they don't charge for their time (the fee is just the entrance fee to the MET), they encourage tipping. Our group was about 20 or so people and each tipped him $20+ from what I could see. So not only do they get to count their time (many non-JWs would follow us and sometimes he would engage them and place mags), but they also get paid. While it may not be put together by the org, the tours were on the schedule for all those that were coming in for the international conventions last year. In one day several hundred, if not thousands, of JWs were touring the MET on one of these tours.