I'm in the group that purposely started their tank with dry rock to avoid hitchhikers. I religiously dip corals too... except for the one time I forgot, and that's how a bristleworm made its way into my tank. I also had a micro brittle star fall off a coral frag I dipped, and plopped it in the tank because it's another "good guy" hitchhiker.
I do know bristleworms are also good CUC and there are many good hitchhikers in general (so I understand the argument for them) but... they creep me out, I can't help it. So I wanted it out of my tank, but never tried very hard to catch it. And then it grew HUGE. Thought it was a fireworm actually because it doesn't look much like a "normal" bristleworm and it has red tufts in between the white... but it hasn't bothered anything and I do see it pop out from under its rock and eat leftover food. So I've resigned myself to letting it stay, lol.
I do know bristleworms are also good CUC and there are many good hitchhikers in general (so I understand the argument for them) but... they creep me out, I can't help it. So I wanted it out of my tank, but never tried very hard to catch it. And then it grew HUGE. Thought it was a fireworm actually because it doesn't look much like a "normal" bristleworm and it has red tufts in between the white... but it hasn't bothered anything and I do see it pop out from under its rock and eat leftover food. So I've resigned myself to letting it stay, lol.