I think the other comments still hold,
Just because there are customers, it doesn't mean that you can make profit from them.
Not sure what their margins are, but someone in an older comment said that Redboxes require foot traffic of 10k+. These things seem to require at a least weekly visits, restock, etc.
Also been awhile since I have seen a Redbox, but do they take cash? I thought they were Credit Cards only.