JAK - Polycarbonate bottles (Lexan Nalegene, clear plastic like acrylic are the ones made with Bisphenol A. It's the second ingredient in the reaction, and the reaction occurs under pretty high heat. They are not 'supposed' to leak much Bisphenol A at room temperature, and heating them up makes more leak. The extent of leakage is much up to debate, as is the true magnitude of effect with Bisphenol A. All the science says "Uh, there might be/probably is a problem, hold on while we spend a lot of time and money checking it out!"

I don't use Lexan for much, it's too heavy. I do have a half liter Lexan bottle I tote water around in the house and in the car. I don't put hot things in it, but I know plenty of people who do. I prefer a thermos for long term heat retention, unless I'm on the trail.

I use a polyethylene bottle (cloudy plastic nalgene) on the trail. Polyethylene is just ethylene molecules all chained together in interesting configurations. No Bisphenol A. I still don't put hot things in it as it deforms with heat. I also use a platypus bladder, which I bet is also made with some sandwiched layers of plastic involving polyethylene. I don't put hot things in -it- either. The only thing that gets hot liquid is a plastic brown cup! Yeah, I'm not worried enough about leachates to carry an aluminum bottle or anything.

Freezer Bag Cooking uses bags that are made of variants of polyethylene sometimes in interesting sandwich layers. They shouldn't contain Bisphenol A, and they shouldn't leak much in any case.

Old water bottles, the crazy interview lady must be talking about the funny taste you sometimes get. The off taste you might get from polyethylene plastic bottles is acetaldehyde forming from the breakdown of polyethylene in sun + heat. It happens very very slowly and humans can taste incredibly small concentrations such as 20 parts per billion. It shouldn't be a concern.