So a mine will magically know when someone logged off?
-1 makes no sense.

Actually each object in the game has an origin - If the devs tagged each mine with its owner Id then it is a somewhat simple matter to find them all. Even simpler is to have the player ping thier own mines once every 10 minutes to stop an auto destruct timer...

Net splits and outages can last for several minutes - I figured 15 to be as generous as possible before tossing all that work in the bit bucket.

Self destructing mines sounds less than sane. I'd rather set mine (hehe) to go dormant and then reactivate when I log back in.

If this self destruction scheme got set in motion, I'll just log in to my phone before i go to bed, and stay logged in all night. (Or at least an hour, which is when normal mines time out) . Meaning I just defeated your suggestion.

Having mines disappear on logoff is one thing, but they absolutely should not re-appear when logging back in as it would be rife for abuse.

"Net splits and outages can last for several minutes - I figured 15 to be as generous as possible before tossing all that work in the bit bucket."

Well, "as generous as possible" would be to just leave them running their full duration. Which is how things should be anyway. Like Knauf said, we can easily defeat a shorter timer by simply leaving the computer running.

Mines should stay active when owner logs out.

Mines should stay active when owner logs out.

For their full lifetime...