[enscr]

For some, P(losing key) > P(key theft)

[crystaln]

P(key theft) is rather hard to calculate, given the entire universe is up against you and you have no visibility.

There are plenty of ways of avoiding losing a key, or generating pneumonics from secure keys.

[intelliot]

Unless this has something to do with the lungs, you mean "mnemonics" :)