I'm with IaaOkeoke. I've never engaged in deliberately spiking farms (as far as I can recall). I've been on the receiving end from time to time. Not a big deal ... you loose a few troops, and trying to track down the spiker livens up the game for a bit.
But not being able to reinforce anyone that isn't in your alliance or confed seems like a terrible rule. What happened to the "enemy of my enemy is my friend" principle? The Machiavellian plotting and scheming? Maybe I'm just a dinosaur from an earlier age, and have to accept that Travian isn't the game that it used to be.