It doesn't matter if you see him in the background or not. That's entirely unrelated. When he challenges you, you'll get a pop-up.

I've never gotten him for a challenge either so I've given up on him
Give a flower!
[url=http://subeta.net/wishlists.php/316670]
Been going to the dancefloor on each and every dance, still nothing. I get that it's not common, but come on!
I've only gotten him once so far.
Same thing happened last year, too =/ Hmph.
Finally showed up once tonight after a long time of not seeing him.
RIP Mom, I love & miss you more than you know. Tell Dede hi.
Ocean Conservation Namibia on YouTube... they do good work! https://www.ocnamibia.org
I have been wondering the same thing. I have been dancing with a variety of people and always make sure to go to the dance floor but have not been challenged at all this year... and I could really use some extra trinkets.
I finally got him, but Im not sure if I am doing anything wrong because Im stuck to tjis page and nothing happens:
Hello Crawler, my name is [NPC] Gossip Boudewijn. You ruined my dance prospects. Pick a weapon and prepare to duel! How monstrously intolerable, there's nothing for it but to choose our weapons again!
Am I supposed to do something special?
You need to choose one of the weapons displayed again to play some sort of rock, paper, scissors with him!
Oh gosh now I got it haha. Thank you, I will do that! :)
Have been dancing mostly with 3 friends since the beginning (and visiting the dance floor), and haven't seen him. I guess he's afraid of me. What a coward. Oh well :P!

I haven't seen him a single time yet, either. He was a lot more common last year.
I've been dancing with one person since the beginning. At this point, I must've visited the dance floor during 50-100 dances. I haven't met Boudwijn once. What gives? I know he's supposed to be rare, and I had a lot of trouble finding him last year, but it's getting ridiculous right now...
I agree, they totally skyrocketed the rarity of the encounter. I finally found him today. I wonder how the heck some people found him more than twice.
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I found him I think 3 or 4 times? The most recent time was the only time I beat him, and I haven't seen him since :/ That was a few days ago and I've danced ~100+ times since then
I've had booty-boy once. that's it and i've danced and accepted a fair number. It's obnoxious, I want to poke him with something sharp. XD
Do you have a rare item that just won't sell? Are you going through the high levels of Item Hunt? Or maybe you just HATE that blue bunny? Then you should join IHH helpers and IHH bargain in the forum groups!
Just viewed 50 dances that I had stored up, and I STILL haven't seen him even ONCE!
I mean, I got the achievements last year, and I'm not exactly hurting for tokens, but it just seems like this should be something I'm able to do.
Where is he?!!!