One might hope, but I wouldn't bank on it... Even if it lands into honest hands the person may not know how to help it find its way home.
For example: https://forums.macrumors.com/showthread.php?p=18477376
Well, assuming it's registered, they could try calling Apple and tell them they found an iPad and provide them with the serial number. In another scenario, on the Apple forum someone found an iPad and did this:
Few steps I did to return it :
1) The key thing to help return the ipad is to leave it charged and not drain the battery.
2) Wait for the owner to ring the ipad as lost and give his contact details. The ipad will ring when the owner claims as lost and can provide his contact details. I got the ring with the phone number.
3) I contacted the phone number listed above and returned to the owner
According to this person this works even if it's locked as it appears on the screen. I think in most cases there's a way to get it back to the owner, if it's registered, and assuming they want to be honest about it. Having find my iPad enabled helps too.