For over ten years now I've been making clear ice in an Igloo cooler in my freezer, a method I first developed in 2009.
You fill a hard-sided cooler with water, stick in the freezer with the top off, and the ice freezes perfectly clear from the top-down, leaving only the bottom part cloudy if you leave it in that long.
When you dump out the ice block, it can take just a few minutes to over 45 minutes for the block to slide out; this often depends on if you let it freeze all the way or not.
Lately one of the take-out restaurants I've been buying from has been using these thick plastic bags that are almost exactly the size of the ice block.
My experiment was: Can I fill up a plastic bag inside the cooler with water, so that after freezing I can just pull out the ice block quickly?
I gave it a shot, and the answer is No. Even though the bag is nearly the exact dimensions of the cooler size, it still wrinkles just a little bit. In any wrinkle water freezes and sticks in the solid ice block. It wasn't super easy to pull the bag of solid ice out of the cooler in the first place, but more importantly I had to melt the section of the block where the plastic bag was embedded before I could separate it from the block, making a wet mess.
In order for this to work, I would have to have a plastic bag with exactly square sides to fit into the cooler. The industrial Clinebell ice machines sell these bags for their systems, but those are 300 pound blocks rather than 20ish.
Alas! You can see on the bottom image below where the bag was pinched in with the ice block.