del_timer_sync() synchronization rules

In the header of the del_timer_sync() function in 2.4.x kernels it says:

* Caller must disable by some means restarting the timer
* for new.

In kernel 2.6.1 the header says:

* Synchronization rules: callers must prevent restarting of the timer,
* otherwise this function is meaningless.

Does anyone know what this is about?

Does this imply that a timer that restarts itself must use some other means
to prevent it from restarting once del_timer_sync was called? (like some kind of terminate flag)

If so - isn't this just what dell_timer_sync is supposed to handle properly?
If not - then what kind of scenario is this referring to?

Tsippy