Back to the basic (Unit) level, no morale check is needed (it is called "Unit is in Good Spirits") as long as:
- no Teams in the Unit are either destroyed or bailed (the latter is only true for Units containing Tank Teams)
- at least one active (neither destroyed nor bailed) Team is within 6" of the Unit Leader. Two active Teams in case of infantry Units.
- Unit Leader is active
There are two major influences of this rule on the game:
1. Units consisting of 2 Teams will have to immediately test whenever one of the teams is gone, or in the case of tanks - bailed. It just hits ITVs so hard that even at 3 points per platoon they do not seem a valid option. Like I described before, you can mitigate this effect by Joining HQ Units or Independent Teams to these guys, but in all honesty: what is the point of protecting 2 ITVs with 2 M1 Abrams tanks or a FIST?
Same goes for fielding understrength Units of Aircraft in US Forces. Each time you take a casaulty, the other guy has to roll his morale check and possibly flee without event taking a hit. The only 2 Team Unit that does not suffer so much because of this rule is the Soviet Recce platoon of BMPs - it will do its job of extending the deployment zone anyway. After this, it is obsolete (or can be used for some harrasment). Poor rules design at this point, really.
2. Going out of command with a part of a Unit is really pushing your luck. Same goes for moving Line Abreast (not so clearly defined in the rules). If the opponent is able to kill the section containing the Unit Leader, the rest of the platoon has to test (even if you only killed 2 out of 10 tanks for instance).
Overall, Morale mechanic of Team Yankee is very similar to FoW but it is really hard to kill a Unit by forcing a morale check, unless the opponent splits it and you are able to kill the Leader.
Update & a fun fact at the same time (confirmed by Phil): if you do not put any of the Formation's Units on the table at the beginning of the game (meaning - if you only start with Support) you do not have any of the Formation's Units "In Good Spirits" as per the rules and thus you automatically loose the game :)
There are about 20-30 special rules in Team Yankee covering high-tech equipment characteristics & tactical doctrines used by the opposing forces. Most of them, add a +1 here or there or make a unit gone to ground when it moves or shoots. There is however, one rule that is really outstanding: Spearhead.
By using Spearhead, a Unit can make a pre-game move when it deploys. Once the move is complete, other Units that have not deployed so far treat anything within 8" of the Spearheading Unit as an extension of their deployment zone!
This extension of deployment zone is limited by enemy teams, deployment area or by any objective. Still, in some of the TY scenarios (like the Counterattack) you can really fast-forward your entire army to be just several inches away from an objective and get a 1st turn charge in or even capture it uncontested. This is huge and I expect it to be used very frequently, especially that in the Soviet Forces you can have more than one Spearheading Unit (each Formation can use one + your support also has the option for one).
Phew, seems I have gone through all the rules of Team Yankee - next mission is: list building :P