tbone, Will this be the case with double AL80s on a cutout SS plate, so minimal fixed mass in back, with all the needed lead on the front of the body? Or if that makes the diver too belly heavy, then the lead distributed more to the sides to align with the divers center? Not wanting the AL80's lead or not wanting lead in front are separate issues.
I'm currently diving with 20 lb. of lead. I have not dove double AL80s on a cutout plate. But that's a lot of lead available to shift my center of gravity to get me trimmed out front/back and head/toe.
Always is not an absolute, if you do a lot of work to get the balance between ballast on a belt in front of you equal to that on your back, there will be a small window during the dive where you can roll on your side and the tanks will be comparably negatively buoyant to your body. Practically though it's not going to happen.
If you chose to dive double AL80's in a drysuit with a lightweight plate and had a ton of lead on a vest or belt, then you would have all of the ballast on your front and when you tried to roll on your side, the lead would just pull you face down again.
The wing also plays into this where a properly sized wing will have gas on both sides of the tank when you roll over and that will naturally want to level itself out. It doesn't really care if you are face up or face down, but it will want to be level.
Practically speaking though, normal divers will have the rigs much heavier than they are and for that, the natural tendency when you roll on your side is to turtle over. I'm sure guys like
@kensuf can back me up, but after you spend enough hours in doubles, even double 104's while cave diving with light undergarments, your body learns what it needs to look like to be able to stay on your side for extended periods of time. It's not something I like to make a habit of, but it's not something I'd consider a problem either.