Solid question and something we think about a lot! Worst case is a weak zipper or similar. We're bringing a new gripper online which is more multimodal - some mechanical grasping, some suction, and the ability to choose what you use. We're moving away from pure suction partly for this reason and partly for textiles.
Suction is great though, and ~75% of bags checked through the US are hardshells, so it's something we're not ready to ignore entirely.
Also good question and something we've thought about. The difficulty there is actually getting the forklift tines out after placement. Actual forklifts in real warehouses rely on pallets as an affordance for manipulation, and we don't have that luxury here.
There have been some neat attempts with short conveyor belts as end effector tools [1]! Generally these systems rely on being able to rearchitect a significant amount of the process (building a controllable conveyor belt or rearchitecting part of the bag-room), and we're focused on dropping into existing processes.
