Exactly - In my experience anyone could share their google docs to everyone under the sun, with or without notification. You don't get asked permissions to agree to have a shared file in any case.

So as long as you don't filter out the share file requests from other people, there's no need to keep the notes about "some stranger has shared this file with you". Coz you wouldn't care.

Though it's probably good practice in comms to inform someone by chat/separate email that "here's a new shared file you should be looking at."