Thought I'd drop a note on this topic.
When starting, you may not have a TB to leave. So, Take one, leave one doesn't work. I collected a few locally to help on their way to their goals, but they ended up getting stuck at their next location, for which I feel guilty since I transferred them to someone else (this is being rectified this weekend). I think if we can truly help a bug towards their goal, then it's fair game, though we don't want to pilfer a cache clean of all the bugs, since others may want to participate, and isn't that the way it should be.
I'm about to release 3 TB's of my own in the near future, and I hope that people help them fulfil their mission, reguardless of the "Leave one, take one" rules. I want my bugs to move, like I know others want theirs to move, of which I will be more careful in the future in how I handle them. Lesson learned.