空中飞人的福音：一种更好的指纹扫描器

    然而，尽管受到旅客的热情追捧，但人们也一直对全球通关计划有抱怨，这些声音——如果只能算微弱的话——是来自少部分在扫描指纹时遇到困难的会员。当那种事情发生时，无人值守亭会显示出一个“X”。这个信号会让该名会员进入任意普通的入境安检通道（或者在某些情况下是进入一条特殊的全球通关计划问题通道）。 但他或她必须像其他人一样接受安检人员的检查，而不是直接通关。

    玛西亚•多恩是伊利诺伊州罗克艾兰一家货运公司的副总裁，她在六个月前成为全球通关计划的会员，有一次她的指纹无法被扫描，导致她卡在一条入境通道中——她试图插队，但无法通过——这让她差点错过飞往哥斯达黎加的转接班机。虽然多恩总的来说还是喜欢这项计划的，但在那个时候她有了别的想法：“我花了100美元就得到这个？”

    这个问题在TripAdvisor和FlyerTalk这样的旅行网站上一直是讨论话题，并成为《纽约时报》商务旅行专栏作家乔•夏基的写作素材，他对于全球通关计划另一方面的“热情”评论包含了这样一则轶事，一位旅客无法完成指纹扫描，直到他在海关工作人员出汗的额头上把自己的手指按湿（说点近的，《财富》杂志主编苏安迪在申请加入全球通关计划时也遇到无法让扫描器读取其指纹的问题）。

    这是怎么回事？

    专家估计，1-4%的人指纹太过模糊，无法被机器读取。有一些特定的群体更有可能遇到这方面的麻烦：跟化学品打交道的人，或是从事多年手工劳作的人，抑或是皮肤干燥和患有皮炎的人。

    这使得机场在读取人们指纹方面颇具挑战性，因为乘客刚从飞行数小时的国际班机上下来，此前他们一直坐在空气湿度只有5%的机舱内（出汗额头的作用就在这里）。

    然而，出问题的并不总是模糊的指纹。扫描器必须以正确的方式按压，手指需要平放在正确的位置，并使用特定的压力。扫描器不干净时也会出现问题——据瓦格纳称，工作人员每天都会对扫描器进行清理，方法是用一截胶带粘走扫描板上的污渍。在无人值守亭报出“X”之前，每个人都有两次机会让机器正确读取指纹，否则他或她就得去见入境检查员了。

    Yet for all the enthusiasm, the program has been dogged by complaints from a vocal if tiny minority of members who have had trouble getting the scanners to read their prints. When this happens, the kiosk prints out an X. That printout allows the individual to cut any normal immigration line (or in some cases go to a special Global Entry problem line). But he or she must still be cleared by an agent like everyone else, rather than cruising straight through immigration altogether.

    Marcia Dohrn, a VP at a trucking company in Rock Island, Ill. who has been enrolled in Global Entry for the past six months, nearly missed her connecting flight to Costa Rica when she got stuck in an immigration line -- she cut the line, but it didn't move -- after her prints wouldn't scan. Though she generally likes the program, the moment gave her pause: "I paid $100 for this?"

    The issue has been a topic of discussion at travel sites like TripAdvisor and FlyerTalk and fodder for New York Times business travel columnist Joe Sharkey, whose otherwise glowing review of Global Entry included an anecdote of failing the fingerprint scan until he wet his fingers on the sweaty forehead of the customs agent. (Closer to home, Fortune editor Andy Serwer also had problems getting the scanner to register his fingerprints when applying to the Global Entry program.)

    What's going on?

    Experts estimate that 1 to 4% of the population have fingerprints that are too faint to be read by machines. There are certain groups that are more likely to have trouble: those who have worked with chemicals or done years of manual labor, or people who have dry skin or dermatitis.

    That makes the airport, where passengers debark from hours of international jet travel -- seated in a cabin where air humidity is as low as 5% -- an especially challenging environment for reading fingerprints. (Hence the utility of the sweaty forehead.)

    Yet it's not always faint fingerprints that are the problem. The machines must be pressed just so, with fingers laid flat in the correct position and applying a particular amount of pressure. Issues also arise when the scanners are not cleaned -- a procedure that is done daily by laying a piece of sticky tape on the scanning plate, according to Wagner. At kiosks, individuals get two chances to get it right before they get an X and are sent to the immigration officer.