While this is not a direct violation of California law SB1386, it is not a long distance to be able to argue that the companies in question are acquiring unauthorized personal information. While we're not talking SSN, driver's license, etc etc., the definition of PII is only going to expand over time.

Basically, if I don't have a personal contract with LinkedIn, it is extremely thin ice for them to be collecting my e-mail address just because I was invited to one of your meetings.