We've been getting lots of complains about this in the Google Places forum because often those map links are wrong. Sometimes they go to a business that's located in another state.
But it's not a Places problem or a maps problem per se. It's that the organic algo is scraping the wrong data from somewhere. I've worked through a few of these with the Manager at Places and she's had to work with the organic team to get them fixed.
EXAMPLE: In one case the company was in another country but the + map link was to a US location. Turns out originally their host listed the host US address on the Whois. Sites scraped the whois, so the business name got associated with the host's US address. And that's how G picked it up and gave the non-US business a + map link to a US address.
Not saying this to throw off the thread, but to shed light on the fact that if G can scrape address data for a listing she MAY attach a +box address.
If you have a business directory, you need to show the address. But if she finds the address, she may create a +map link. I'm not sure there's a way to avoid it.