New here. Hi all. Regarding the the DEF, Prist conversation, I work line at the sole FBO at CLT. Not sure about other places but we have a Prist tank and a DEF tank on all our fuel trucks. So the Prist gets mixed in in the fueling process with the turn of a knob if requested. Obviously the DEF and Prist tanks are clearly labeled but mistakes could happen. The DEF and Prist refilling areas are clearly marked and labeled and are kept about 100 yards from each. Further making extra steps not to confuse or combine the 2.
If you're ever at Wilson Air at CLT during the night say hi. I usually have a smile unless a Lav is requested