I know a lot of others may feel differently but I wanted to start a discussion about this. I can't stand when someone comes and starts mining a rock that I'm still working on. Yes, we should share, but what about having the option not to? The rocks regenerate so it's not like people can't come back or find a other rock.
What I propose is, once a user has started mining a rock, if someone else tries to mine it, having a little bubble pop up for the original user asking if they'd like to share. Yes or no. Also, if a person wants to stop mining in the "middle" of a rock, they can have the option of "abandoning" it via a menu. Then it would be open to be mined by someone else. There should also be a timer that automatically makes a user abandon a rock, in case he or she is AFK in the middle of mining. Maybe 5 minutes?
What do you all think?