Yeah. There may be a good reason with Julie. But I am ignorant to how that works. I live in a small town, and to find someone here, you just need to walk outside. lol Getting away from people around here is the hard part.
But finding numbers can be what happened. it's like when Mondler met that couple, on their honeymoon, who didn't like them. Then they look in the PB to see that they got a fake number. Least I think that's how it happened.
I think it was more weird how they made the deal. Megan books The Swing Kings, and they don't get the band unless she gets the dress. At the episode's end, Monica is wearing the dress when she tells Chandler she booked TSK. So if she got the band booked, why not just keep the dress? What would Megan do? Unless Monica handed booked YET, but was going to and just told Chandler she did, since she was planning to.

If you're gonna pretend to cut her hair, at least put some scissors in your hand!

A similar thing happens in the Nap Partners episode, the woman that Chandler dumped at summer camp for being too fat, Julie Graf. They suddenly rock up at her apartment to apologise, but Bing hasn't seen her in years, so how did they find her address?

I just assumed she looked up the number. Maybe Monica is listed.
Or, they enjoyed chatting in the store where they met, and swapped numbers. Maybe to hear about one another's additional plans, or check out how their weddings go afterward.
Wasn't something I really thought too hard on though. lol

If you're gonna pretend to cut her hair, at least put some scissors in your hand!