I love the camera on my cellphone.  It protects me from meter maids writing a ticket for my car before the time expires.  I snap a photo of her (or the ticket, if I just missed her) and the camera time-stamps it.  I snap a photo of the meter, if time is actually remaining.  Then I immediately upload to twitpic.com to preserve a time-stamped record.  No need to worry about being believed; I have time-stamped photographic evidence.  Best of all, I  am never tempted to stick gum in a meter, because I am a thinking adult, not a twelve-year-old.