Well, by the end of the game in option 2, the players can choose to cancel/Draw the game if they so choose. I think that you will always have people who will take advantage of others at any opportunity, but hopefully you can post some friendly reminders about integrity somewhere.

Personally, I know that you can't always get to things in time, or that you can't always determine how best to handle a situation. I know that things can be difficult to manage when you actually have a life outside of this game. (In hoping that you, of all people, do have a life outside of this game.) And because of this, I know that not everything will work out perfectly, and I would hardly care as to how you get things done, so long as I can play my games and win where I can. So, I'm not really looking to complain about whether or not you're doing things right, I would prefer it if you did not reset any turns in games that would require such, but leave it to the players who are within the game to handle things for themselves after you have received the complaint.

Nevertheless, I think that whatever works is good enough. Just so long as no one is too annoyed about it.

- Reset the turn and change the wrong move to "hold" or "disband".
This seems the better choice to me.

- Reset the turn and change the wrong move to "hold" or "disband" and tell the player who complains to get over it ;)

Personally, I always report to Oli a wrong link on a map as I discover it. Whether I need the correct link or not. Even if I discovered it by chance, reading the options into the move/support/retreat menu.
Why do I do this way? Because I never thought there could be a different option.

I think that keeping this site error-free and enjoyable for all is a responsibility of all users in here.

But I'm not surprised to hear that some lazy players don't report errors, although I blame them. We're here for free. Oli provides us this beautiful site, working for free. The minimum we can do to help him, it's spending 2 minutes reporting errors. It should be our way to thank Oli.

I'm not even surprised to hear that some cheater doesn't report AND takes advantage of the error: I saw it a couple of times, with my eyes.
I believe they know that someone will complain to Oli. But they also know that Oli has a RL and little time to spend here, so they know they'll probably succeede in taking that unfair advantage. They will succeede and Oli will have to read a lot of complaints.
Anyway Oli will have a lot of unnecessary work to do. That's the way those cheaters thank Oli. :(

What I am surpised to hear is that they _usually_ claim "they didn't know this was an error".
WHAT ?!? Really ?!? Are they trying to convince us that they're just stupid idiots?!?
Say Classic or Modern or Abstraction: you moved/retreated from WestMed to Rome... and you claim you didn't know it was an error?!? A fleet from Tuscany to Naples and you didn't think it was an error? Really?
I believe that whoever claims such a thing like that is not only a cheater: he's a coward liar, unable to admit he was just trying to cheat.
At least in 99.8% of cases. There could be a 0.2% of absolute beginners or narcoleptics or real idiots (or probably more than 1 of these 3 things at once).

So I vote for:
- Reset the turn and change the wrong move to "hold" or "disband".

First times it will be time-expensive, sorry Oli. Sometime it will not possible because you will be busy or something. Alas!... We can live with it... nothing is perfect.
But I'm sure that in a few months everyone will learn that trying to cheat is backfiring: they'll have a disvantage. Better for them to cooperate and report errors. Power of deterrent!

So, in the mid and long term, you'll save your time and all games will be more enjoiable for all the honest players. And I'm sorry for that 0.2% but:
- Absolute beginners will quickly learn that a New Variant may contain some errors. They should expect some error could be in. So they'd learn that they must discover and report errors. NOT use them.
- Narcoleptics will learn to make sure they're wide awake before they press "save" or "finalize";
- Real Idiots.... are there really some in here? :-)

Reset the turn and change the wrong move to hold or disband. Just resetting the turn would be the ideal solution, but unfortunately we all know there would still be people who would use an illegal move to get a glimpse of other players' strategies when it came up if there was no penalty, so this solution seems more practical so long as it's clearly stated in the rules.

so that's 4 people in favor of resetting the turn and change the wrong move to "hold" or "disband".
and 1 player ambivalent.

Personally I think that this solution would place greater emphasis on players doing the right thing and reporting issues by forum or by PM.