响应redanqi的建议 (http://www.instrument.com.cn/bbs/shtml/20080528/1278955/), 说一件大家讨论 fail safe (失效保护; 失效保险; 故障安全 etc. see http://www.instrument.com.cn/bbs/shtml/20080519/1267857/ )时想起的一件往事。
Several years ago, when I was passing through the security check point at an airport, I suddenly found that my film was still in my luggage which was just put in the X-ray scanning machine. I asked the officer to stop the machine and explained that my film was in the luggage. The officer pointed at a sign on the machine and said “No problem”.