Gavin,
Yes, most suppliers do not provide the same top-of-the-line quality control for discount retailers like WalMart, but that is really not WalMart's problem...They ask for bids from companies that can fill WalMarts needs at the lowest price....and I'm sure WalMart does not expect to receive pre-mixed 50/50 anti-freeze that freezes at temperatures above 0 (F) degrees.
If a WalMart customer had engine damage, I'm sure WalMart would win any lawsuit against the company that actually made and sold the anti-freeze to WalMart....assuming it was not made and bottle in China...:grin:
...Rich