I took my dads' van to Wal-Mart to get an oil change back in '93 and they topped off the brake fluid with power steering fluid. Lucky for me the guy left the bottle in the van, anyway. I got the van home fine, but when my dad left to go to work he made it about 5 miles from the house and the brakes locked up on him. So, he had the van towed back to Wal-Mart and they actually had a written record of the power steering fluid being added to the brake fluid.
All the rubber in the brake system had to be replaced. They paid for dad to have all the brake lines, calipers, and brake cylinders replaced. Funny thing is I told the guy at Wal-mart that power steeing fluid was not supposed to go in there. Just glad my dad knew that I was smart enough to know that was not right and I hadn't been the one that did it.
BTW, I did tell my dad I saw the guy do it as soon as I got home. He thought maybe I wasn't paying attention. I don't get oil changes at Wal-Mart because of that foul up.