Yes, I'm afraid that the flipflop...

Yes, I'm afraid that the flipflop insulation theory was, as you suspected, flawed. Flipflops might conceivably reduce the shock from a 240v mains supply. But they would not help too much with the 10-120 MILLION volts of a lightning strike. The flipflops themselves might actually survive, intact, as the current would bypass them and leap directly from the end of little pink toes to the ground. But the flipflops' moisturised organic cargoes would be totally crisped, regardless.

Heading South?