That's something I always wondered about WS. Doesn't putting a container with a clear lid in a bright, sunny spot cook the seeds on the first really sunny day?
Maybe milk jugs are cloudy enough to keep the extra heat out?
The one time I tried WS, I put them in full shade (under a porch roof). If I was going to put my clear-lid containers in the sun, I would vent them well.
But I have almost no WS experience, just fears.
