[yardstick]

HR / Recruiter setting up interviews? The person doing the inviting might be different from previous calls/emails.

Customer meetings I get invited to often come from someone I’ve never dealt with before, but include others who I work with who were responsible for bringing me into it.

[saghm]

I think there's a pretty big gap between "people at my company are allowed to add things to my calendar" and "random stranger anywhere in the world can add things to my calendar".

[yardstick]

Neither of the above examples would come from people in my company.

[saghm]

"others who I work with who were responsible for bringing me into it" sounded to me like people at your company, who I assumed would be able to add you to the meetings. I guess I might have been mistaken

[yardstick]

Depends on who is running the meeting. If the customer is hosting, the others I work with will provide my email to the customer so they can add me to the invite.