You don't have to have an account on LinkedIn to receive these emails. We were getting them sent to OTRS email addresses all the time before I asked LinkedIn to block emails to the addresses. Had to go through customer service because they don't provide an opt-out link in the emails they send. We still get some to a few addresses I asked to opt out of. I thought I also asked the list to be opted out as well, but potentially they received a bounce email back and so disregarded the ticket.

The main concern is people need to stop uploading their contacts lists and then telling LinkedIn to invite *everyone* in it. Take the time to select actual individuals rather than spamming everyone.