Since we have a cash back credit card I use it for all transactions where the card never leaves my hand.
Cash for dinners and such where they want to hold/take my card.
Every compromise happened at a gas station or dinner where the card was out of sight.
Since our fuel purchases are small, 10-13 gallons, the 5 cents (typically) savings (50 to 65 cents) is not worth the increased theft risk, IMO.
I minimize theft risk by pre-pay for diesel when I can. My driver information center shows gallons used and is pretty accurate. I multiply the gallons used by the price per gallon and only prepay for that much; then zero it out for the next stop.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW