Does AI delete captured units?

I was wondering what would happen if I flooded an AI player with worker units for them to capture. I am worried that if I try this I will be wasting my time because the AI may just delete the workers they dont want. I would really appreciate an answer, thanks.

They tend to autodelete any workers they manage to capture inside my borders. Other than that, I do not know very much.

City-states do sometimes delete units you gave to them.
Gifted old units to other AIs won't be upgraded unlike in civ4.