In my state cyclists are required to used their hands to indicate a turn, only if safe. It is likely that lights would be illegal, since the state requires signals lights to be visible to vehicles in front (oncoming) and behind. There is no provision for bikes to have lights either, so if pretending to comply you really need to comply. This is why I’ve often viewed the lights as unsafe gimmicks more than anything else—creates a false sense of security—and for people in unclassed e-bikes a great way to make it harder to avoid a ticket if one is issued and others racked up. Want to act like a motorcycle get one, otherwise learn the ways of the bike Jedi. It really isn’t hard to signal when practicable and if a car is ever following me so close when I’m coming to a turn then I’ll be slowing down far more then normal and making sure I can give a quick signal.