When I was a kid, back when everyone checked bags because there were no overhead bins at all (just racks for the coats and pillows, if you recall), there'd be someone at bag claim whose sole job it seemed was to compare your bag check tag with the claim check issued by the airline.
This prevented honest mistakes, since, as we know, all bags do tend to look alike, especially after a long red-eye flight. It also prevented simple theft. And yes, people do steal bags from airport bag claim carousels.
You only have to do a web search for "theft at bag claim" to see how prevalent the problem is. Just ask Anthony Hargrove, who has been arrested at least 12 times, and convicted five, for stealing bags at Chicago's Midway and O'Hare Airports.
Of course, there are surveillance cameras everywhere in airports, and anyone who does this often, as Hargrove did, will eventually be caught. Eventually. Keith King, 61, and his wife Stacy, 38, were found with almost 1000 pieces of other peoples' luggage in their Waddell, Arizona home, all of them stolen from bag claim areas at Phoenix's Sky Harbor Airport. So apparently security cameras aren't always the answer.
But now it seems that many airports and airlines have done away with these bag check checkers, as a cost cutting measure—which is ironic since they now charge a fee for checking a bag.
True, some airports and airlines around the world still check, if only at random. Recently, I tweeted "dear airlines: please bring back those people who compared bag tags with your bag receipt before you leave baggage claim" and it got nearly 100 "favorites" -- so I'm guessing I'm not alone in being paranoid about people walking away with my own or someone else's bag, whether intentionally or not. Several people tweeted back, "The best solution is do what I do, don't check bags" but this person forgets that the only reason there's room in the bins for his bag is precisely because some people check their bags. (By the way, I, too, rarely check bags, but sometimes there's no option, like when the airlines send you back to the check in desk because your bag is one inch over the size limit.
Someone else suggested that bringing back tag checkers would be a "nightmare" and cause jams at the exits, but probably not since bags don't all come out at once. More than one person tweeted back that airlines would start to charge extra for bag tag checking service, but I think they already charge enough to check bags (how typical that after they started charging, they reduced the level of service.) But one person had a good idea: with the advent of electronic bag tags (British Airways and other airlines are experimenting with this idea), people will be able to scan the tag before leaving the carousel area, perhaps going through a turnstile to exit, like on the NYC subway. After all, they'll soon be tagging their own bags at home and scanning their own boarding passes to get on the plane. So why not this, too?