If you need to remove a master link at the side of the road, you just need a rock. Pull the master link into a pyramid on the chainring, so that one side of the pyramid is the master link. Hit the top of the pyramid with the rock, and the master link will come apart. You can tighten it using pressure on the pedal while the master link is in the top run of chain, as mentioned earlier. Pay zero attention to the idiot that tries to do that using the bottom run of chain.

You could paint the rock park tool blue and use one side for 7-8-9 speed chains, and the other side for 10-11 speed chains if you want.