Have you been playing with the same players each time?

This actually happens somewhat often, and some players are more susceptible to it than others.  For instance, P5yy dropped like crazy one day.  On another day, it's somebody else.  My theory is the combination of the Alloy code and some freekiness of the users connection on that day (i.e., Thunderstorms) cause ICO to drop you.  When it drops you, you get to play against a bunch of AIs.  It occasionally happens to me, but not consistently at the same time.  If the host turns off Alloy, this usually solves the problem, but not always.

Well, I wouldn't tell them to turn off alloy, I would suggest it.  In order for them to turn it off, and host, the host has to have their router setup properly, go to host settings (which will kick everyone out of the game lobby), disably alloy, and rehost the game.  So just be aware of the prereq.

Otherwise, no, there isn't a lot you can do about it, just make sure your connection stays stable.  But really, it's all just voodoo, as sometimes ICO will just burp and throw everyone off.

I am having the same problem, it happens everytime I play online.  I get booted from inronclad whether or not I am hosting...

I have had the game since november and have been experiencing it everytime I play since then.  I have always kept my game patched and now have entrenchment and I still have problems