In a recent story, I noted that because the Transportation Security Administration (TSA) must be able to inspect bags, it is best to keep them unlocked or to use a TSA-approved lock, which screeners can open with a key.”I cannot tell you how many TSA-approved locks I have had cut off by screeners. Apparently they didn’t get the memo that they have a key,” reader Kathy Burke of Chanhassen wrote in an e-mail. Kathryn Christenson of St. Peter, Minn., phoned to say that her TSA-approved lock was slashed by inspectors in England. “I think you should tell people that those locks are for travel in the United States only,” she said. Good point. So perhaps the best advise is to follow Burke’s example: “I now use a twist tie to ‘lock’ my luggage,” she wrote.