A major river case to think about

[plloyd1010]

No, I don't think that.  I'm pointing out that that the tank simply cannot enter the hex, nor can it assault the hex as long as the Polish unit is in the hex.

That is incorrect. Rule 5.75:

Units in a river hex (whether they're crossing or not) can be attacked normally, even by Assault (12.0). If units assault into a Major River hex, the attacker suffers a -2 column modifier on the first assault round IF neither side has an ENG in the hex.