On Linkedin, often I get connection requests from people I don't know. Most of the time we share 1-2 connections and/or studied at the same university. Sometimes we don't have any mutual connections and don't seem to have anything in common, so I have absolutely no idea how those people find me. I send connection requests only to people I know personally, but I accept 99% of requests from other people even if I don't know them, because why not, having more people in my network might be useful.
I'm afraid, however, that it might look unprofessional, and that somebody would ask me: "Hey, I see you have Jon A. in your Linkedin network, we worked together at X! Where did you meet him?". And I'd have to admit that I have absolutely no idea who Jon is and that I can't even recall this name. In fact, I had this situation once during a job interview several years ago, and it was super awkward, the interviewer then asked me: "So, do you know Jon or not? Do I get it right that you don't remember Jon? Why did you even add him?".
Is it okay to accept requests from people I don't know? Can it make my profile look less professional?
Upd: I see it's a duplicate of LinkedIn invitations from people I don't know , couldn't find that question before asking this one.