General rules for online games.

As for recruiting neutral creatures: I've never seen anyone join me in The Eastern Lands maps in Heroes of Might and Magic.

You seem to have a misconception about recruiting neutral creatures. Yes, those initially generated on the map as guards for objects or artifacts are unlikely to join, at least I haven't encountered that in practice. However, we're talking about neutral creatures that appear on the map as a result of their weekly spawns. For example, playing as Carl, when the Stork week arrives (which increases the growth rate of Swordsmen by two), I can recruit as many Swordsmen as I want. I'll specifically load Carl up with troops, and every second Swordsman stack that appears as a result of the Stork week will ask to join me, and there will be a lot of these stacks on the map. Thus, it is quite possible to recruit 1000 Swordsmen into my army without having any growth for them at the start, and this is precisely what the rule about recruiting prohibits.