Activity is a big part of this game, and it's the reason this game does not have a bigger playbase. It revolves too much around activity opposed to skill, and while you could say that this suggestion takes away the need for both, a lot of the posts here are unecessary hostile.
The risk of abuse is present, especially with stealth mobs and rushes. This would of course have to be a feature for "normal attacks". E.g. eta 5 attacks, with geos and 2/3 of the mobs value in visible units. The only routes who could abuse it then would be routes particularly good on the ranged tick, but tbh, if you're not able to a) defend against or b) get your robot player to send out from an incoming RPG player, he'll be dead after the first tick anyway. Same goes for the RPG that gets mullered by an SA - you need defence to be there first tick, or the player has to send away.
That leaves the risk of automating the game. This has to be valued up against the risk of not getting new players to stick around. There have been a lot of suggestions and implementations over the rounds that have slowly taken away some skill from the established "leet" players. The live clock makes eot sends/recalls a breeze, for example. However, while this suggestion too takes away the need for something the core playerbase has in abundance, it's hardly game breaking. You will have to pre-decide wether you're going to be staying for three ticks or not, and, opposed to normal attacks, you can't change your mind and stay for three ticks if you've already given the orders "recall on attacking for 2" when sending out the mob. It does not alter anything; it only gives you an option to being online in an hour - with a catch. Kind of like sleepmode.
Bear in mind that this would be of very situational use if implemented right, but it would allow the casual player to participate more, without weaking the position of the experienced players.
The more I think of it the more I lean towards agreeing with the suggestion.