We have in the past have had a few issues with putting the wrong fuel in equipment . The last 3 seasons I have done this and it's 99% effective . I use zip ties for what fuel goes in which machine . Red for gas .
Green ties for diesels .
The machines that have similar hydro tanks nearby I also painted the caps and zip tied the hydro tanks.
The mixed fuel is tag with a purple tag .
We have 8 - 1 gallon fuel tanks for mixed fuel ONLY. I personally mix the gas for them . The one time I let my guard down A brand new saw was ruined . I managed to repair it with after market parts .
Fuel pump handles also colored . GAS
Also have signs up in cold storage , lunch room / gas shed .