ItsJustMe

It's not directing traffic, it's making a suggestion. The other driver has no legal responsibility to pay any attention to me (unlike if a police officer is making the motions). It's one piece of information that the driver can take into consideration.

I motion people to go around me all the time and hardly any of them ever do. It's amazing to me when someone in a 6.5 foot wide compact car doesn't think they can get around me when I'm riding in the middle of a 2 foot shoulder beside a 14 foot wide lane.

sudo bike

Placing a hand out warning someone about a dangerous situation is not directing traffic, and you aren't going to be liable for anything anymore than not warning someone about a dangerous situation you see ahead. Waving people by... yeah, maybe, I guess, but you'd have to be extremely unlucky, and I think your chances are probably still basically nil that anyone would find you liable for jack. In some cursory searches, I couldn't find anything indicating this has ever actually happened. This is pretty common behavior in rural communities where there is often only a 2 lane country road that passing needs to happen on. The lead car has a better view, so they'll often wave people by as a courtesy. This has been my experience in pretty much every rural community from mountains to farmland on two-lane roads. City-slickers worry about liability more than country folk, I guess .

As to whether you should/does it help, it depends a lot on the road. If you have lines of cars passing you it seems kind of useless and overkill. If you're on a country road with few drivers, that sort of communication is usually pretty common between drivers, in my experience. Not out of place at all.