Question on stacking

[CaptEggman]

Hey there, still trying to conquer France and figure things out at the same time :)

I've learned about the absolut max stacking that prohibits movement into an overstacked hex - makes sense. I've learned that exceeding the road stacking limit kills movement points when entering an overstacked hex - ok. But there seems to be no other penalty except for the maximum fire than could originate from a hex or am I wrong? No penalty on getting fired upon? I guess having lots of men and vehicles in one hex will make for a juice artillery or bomber target, but otherwise my men don't seem to be in more danger when this close together. 

Am I getting this wrong?

I'm asking because I was pondering whether to send a unit across a bridge this turn, into an overstacked (road) hex, or if I should wait for next turn when there is more room. The whole thing is very interesting to me. Getting my units across the Meuse *fast* is a logistical challenge to say the least. I'm dealing with actual traffic jams and I'm loving it. 

Anyway, thanks for any help. 
Have a good one!