Just thought I'd point out that if you buy two locks, after using the first one the cooldown timer will start, and when it expires the flag will need locking again. It's really quite convienient that theres a 45 second cooldown for a 45 second lock. So if you're one of those champs that likes to backdoor/lock/port back to base and then go do it all again, use the cooldown timer to calculate when you need to port back in.
This will be common sense for a lot of you I know, but I think its worth pointing out.
I'm not sure if something like a silence would disprupt the technique or not. Whatever.