Well here is one of the comments made by the Esim employee:
Volcano posted: "Well, not really -- basically there is no 3D crew, so there is nothing to shoot while unbuttoned. AFAIK, the only effect from unbuttoning is possibility of splash damage on the unbuttoned crew member, but even that might not be correct now.
As far as the hatch is concerned, it depends on how old the vehicle model is. Some vehicles do not have a hatch represented on the armor model, some do (the newest ones).
All this is known however, and it will take 3D crew to improve the current behavior."
and then
Rotar posted: "Just checked and being buttoned up does protect against HE artillery."
and then
Volcano posted: "OK, good to hear. "
This is what I think:
As far as I'm concerd and this is my personal opionion. The damage models on Steelbeasts are inaccurate and are quite far from accurate. There are many instances that I have came to such an opionion, this one is one of those. Another instance is shooting a Hind over 8 times with a 120 MM tank round 6 of those were MPAT Air proximity and the others were sabot. In the AAR report many of those hits show in the pilots cockpit and even the Sabot hits show in the cockpit. The player in the Hind at that time claimed to have suffered heavy damage but when I checked the report for that mission. The report only showed that the Hind recieved radio damage. I believe that the networking in mulitplayer may be bugged from the packets that the host and client recieve but really not sure.