If I am waved through and I am certain that no one else is in a position to steamroll me, I will take it with a smile and a wave back.
What annoys me is when someone else has the right of way, but, I perceive it to be unsafe to go, so I wave them through and they just sit there. This results in me having to stop and plant a foot. Having to plant a foot unnecessarily makes me want to plant a foot somewhere else. Do I need to say where?