You talkin' about me?
This. I haven't been around for very long but my spidey-sense also tingles when I see usernames like that. Yesterday, I wanted to merit a newbie for putting some obvious effort into
this topic, but their username followed that pattern and together with their low activity, I just couldn't bring myself to do it, I don't know why.

I had to take a look at the PMs in my inbox to see how many requests for post history reviews I've gotten from members whose usernames fit that pattern, and there were two (though I deleted the ones from members I've banned from making further requests). And it seems like the members with four digits after the name are the least likely to make decent posts--granted, I'm not presenting proof here, just saying what my own spidey sense is tingling about. There are a lot of fine, upstanding members of the community who have the [Name][1-3 digits] format as their bitcointalk handle.
Maybe all of that is in my head, but I distinctly recall the time before the merit system when I was tagging shitposters and I'd come across that pattern constantly. End of off-topic rant.