Chris and Larry.

I've been the "happy" recipient of Jet A mixed into my 100LL twice in my
life.

Once at Elko, Nevada when a tanker dumped his load of jet fuel into the
avgas underground tank and I, and nine other pilots, filled up there before
the mistake was discovered. The second time was the infamous Chevron fuel
debacle that hit a bunch of California airports back in the 90's, with my
LNC2.

In both cases, I sumped the tanks checking for water and fuel color. Also in
both cases, the fuel in the sample tube looked clear and blue. Of course,
had I suspected anything amiss and put some of the stuff on a sheet of
paper, I MIGHT have noticed the oily residue that's supposed to show up -
but I didn't.

I doubt anything has been added to either fuels to make a mixture look
"milky" - but anything is possible, I guess.

As an aside, these two incidents have really made me a firm believer in
filing flight plans, particularly on long cross-country's. In the first
case, the authorities located me at a very remote fishing lodge in the wilds
of the Idaho back country to let me know that the airplane (parked at West
Yellowstone, WY) was grounded. In the second case, they contacted me at my
home in SoCal (at that time) though I had tanked up with the bad fuel about
400 miles north in Sacramento, CA.

Regards,

"Jet A Dan" *

* (Nick-name given me by some of my smart-a** flying club buddies)