Well, you see, new airliners have ignition keys, but after a while, with nightstops and all, they get lost.
When the crew misplaces the airliner keys everyone has to go back to the hotel to look for them, while the gate staff is left to make up stories about tech delays. Sometimes if the airplane isn't too far from base they send a spare set sent out, but eventually they have to get maintenance in to hotwire the airplane. That happens a few times and they just install a switch.
You'd think it would be a security problem, but seeing as you can start most Boeings with the keys from an old Chevy Impala, it doesn't make much difference.
[Edited to fix an ugly line break.]
[This message has been edited by Luftwaffle (edited 10 April 2001).]