I assume what you are trying to say is that the log out allows them to choose when to do the more risky travel to and from towns, but other than that, they spend the same amount of time and take the same risks as someone who is not logging in/out?
One solution then, would be to make it so that when one choses to log out, the character calculates the path back to "home" or "nearest city", then starts walking on it's own according, and disappearing once it enters the destination. This would need to happen after quite a bit of time to Buy Albion Online Silver, to prevent crazy stuff like people inside dungeons suddenly walking in the other direction in due to lost internet connection.
I'd be perfectly happy with an automatic travel back to town, even with the risks involved, but as a programmer I think this might be quite difficult to manage for a large number of players with multi-zone pathing and other fun stuff.
It makes little difference whether it's someone logging in on top of the chest or someone entering the zone in just enough time to reach the chest when it spawns Cheap Albion Online Gold; you still must choose at a moment's notice whether to deal with them by force or concede to them the same opportunity at the chest.
And even a variation as short as 10 minutes would be enough to discourage chest sniping without unduly inconveniencing anyone already ingame waiting for it.
Unless, you know, he has a second character/account logged in. Or he's in comms with a friend that is keeping an eye on things.
But yes, he wouldn't have quite as much information about what's going on as if he was there viewing it himself, but it's still a non-gameplay mechanic that has a huge impact on gameplay.
If you want it to be part of the game, that's fine. Make it a Camping skill. Have it affect how quickly you log off and how long of a delay you have before using your skills after you get more safe albion online gold. It could be it's own skill line or you could just base it off of Adventurer level. Add an additional tool called an Albion Army Knife that allows you to log in and out of zones without penalties if you have the proper tiered AAK for the zone/dungeon you're logging out in.
Then, it's just part of the game, and will need to be balanced in the same way that any other skill or ability in the game needs to be balanced.