Do you know who Dan Austin is? He's a MapMaker expert and an awesome rad dude! I think all Local SEOs should be aware of him and read everything he writes or that is written about him. He recently provided some amazing insight over on Mike Blumenthal's blog that you MUST read: Google MapMaker Update Summary: One Database to Rule Them All. You should also read this interview Nyagoslav did with him back in February 2012.
I asked Dan some questions about finding and reporting spammers in the comments of Mike's post and his responses need to be shared. First, let me explain why finding and reporting spammers is something you want to do...Tactic: Finding and Reporting Spammers
It drives me nuts when I see spammy listings beating my clients in the local search results. I'm like this:
The worst part is that reporting them for spam seems to do diddly squat. Report all you want, but they'll still continue to rank above your clients and you'll continue to destroy cell phone after cell phone. It's quite the aggravating (and expensive) cycle.
If Google would actually do something about it, then you could bump the spammers out, thus moving your clients up. [...]