I have been using the reusable grocery bags for decades. I too have a mobility issue and cannot lift anything heavy. As a previous reader wrote, the cashiers load the bags full and yes they are too heavy to lift.
As I am unloading my cart, I place a bag first on the conveyor and then the items I want in that bag, then another bag and the items. I repeat this process and I am able to put all refrigerated items in one bag, produce in another, dry goods in another and so on.
When I get home, it makes for a speedy unpacking. No more opening and closing the refrigerator or freezer door numerous times. Since I am “loading” the bags on the conveyor I know that I will be able to lift the bags.
Most cashiers know this process but it’s always nice to remind them to only put the items behind the bag in that bag. This will also save you time and no more cans rolling out of the plastic bags and hiding under a seat or in the corner of the trunk.