(was going to post in the Carebear thread so do merge if it doesn't merit it's own topic)
Visitor Debuff, while having some good things about it, is just another mechanic that takes choice away from players because if it's something like a 'disarming at the gate' As Jorb put it (that's a great concept and V.D is a good way to represent it) however the visitor was never presented with the choice, which is taking away from the sandboxy elements by forcing your hand one way or another.
Now if Visitor Debuff only happened if the visitor does some action outside of the gate. whether it's a clickable object or a hearth magic thing ritual etc that was more or less consenting to having the debuff that ties their hands behind their back, most problems with it seem solved, and provided people are still remember how to live with their gates closed, shouldn't cause a lot of issues on that end.
This still means that you can show off your town, or let relative strangers in the gates, and have open trade hubs etc and do everything you can do with the current V.D system, because you just don't open your gate to those who refuse the debuff because they've obviously got something nefarious in mind.
But anyone who either comes across those who left their gate open, or robs someone who carried around their master key or whatever the scenario may be, shouldn't have to break down a wall because the open gate is invalid, and the issue of forcing sandbox players into something if fixed.