I'm adding my vote for this, even though I used the token-mod approach in the past and stopped using it (not for any flaw in the script). I have a rather chaotic group of players, but they weren't trying to cheat, they just don't listen so well (when I said "everyone stop moving" on transition to use of initiative) and/or were "trying out my next move" (which gets really confusing for everyone else). It was really only a couple who were problems. I found that just implementing a lock for one game session annoyed them all so much that the problematic ones actually stopped misbehaving when I stopped using the lock feature in the next session after the others complained, but told them I'd resume it if they all didn't behave. Peer pressure in action. Educating them about using the ruler to plan moves may have helped as well. The reason it annoyed them was because it requried a delay after I advanced the turn order before they could actually move, due to me having to click a macro to lock the old player and another to unlock the new, and then have the result propagate to them (did I mention they're impatient?). But inattentive players and/or ones trying to gain an advantage (meta-gaming) seem like universals to me, and probably more common in new players than experienced ones. Having a way to enforce "not your turn, you can't move", seems like a really good basic function for a VTT to have, not something that should be locked behind "Pro" status. If Roll20 does this, it would be very nice to have it as an option on the turn order (if it's not your turn, you're locked), as well as a command in chat (that could be invoked by macro). Note that you do need a way to allow a player to move outside their turn (5E allows readied movement as a reaction on someone else's turn, for example). A right-click menu on the token could be useful for that, although a chat-log command you could also invoke by macro would be sufficient.