Not all ice cream has a seal, just the cardboard cap. I think that Sour Cream and Cream Cheese containers all have some sort of protective covering though.
You're right about the batteries. Some scissors are like that too with their hard to open packages.
It's been a long time since I've seen ice cream for sale in cartons that aren't sealed, other than in the context of somewhere like an ice cream van or hut that pulls soft serve into a container in front of you.
I can't stand the blister packaging that means about the only way to get into it is to use something like a Stanley knife to cut away the plastic. The packaging is a pain to work with and then, once it's cut open, it's a pain to get rid of because you can't recycle it and the edges are prone to puncture a garbage bag.