Forum Rider Down and/or notification of minor incidents

Absolutely.
Waving others through is dangerous for just this reason.
My driving instructor taught me never to wave others through, nor to be 'waved' without assessing the situation myself.

This.

In addition, one shouldn't let people out/through against the right of way, as other road users may not be aware of your actions.

Obviously this is hard to stick to when traffic is solid, and there are no natural gaps for drivers to turn into...