FED, I remember one tale, apocryphal?, of a pair being tanked to the Med by a Valiant. After one bracket over France the pair apparently peeled off for a closer look at a big lake with a huge fountain in it.
They then asked the Tanker what it was and came back for an unscheduled top up.
I think I heard that on the AAR (IFR - went it didn't relate to IMC) course, probably as a caution to follow the plan to the letter.