EL wire hooks up to inverters. Those require a precise voltage at what the inverter is rated. Anyways, you're going to want to use something like a PIG to handle this. Or even a relay that triggers on flasher voltage. Flashers are pulsed and overdriven. You cannot hook the EL inverter to the flasher circuit directly.

EL wire is also very dim which makes it a terrible choice to go off with a flasher.

I've actually had these inverters catch fire. Not just smoke but actual flame. This is nothing I would ever want to be overdriven by flasher circuits (which actually run closer to 18v in pulses).

GI is A/C unfortunately and won't run an inverter properly.

You're particular success does not negate the potential problem. Inverters are absolutely not made to run past their designated input voltage. Different flashers are handled in different ways and the voltage far exceeds the inverter spec. "It seems ok for me" is not a counter to that. As for the pig2, it's actually made for this purpose. There's no reason not to use something like that.

Yes