Across all social media platforms the strange unknown invitations or requests to connect pop up. The people without photos, or photos of a hot model, or a small number of connections, etc. The red flag goes up and not only do I ignore these but also make the effort to block and report them. The more people that do that the quicker these guys are flushed out of the system. It's the scam artists or malware distributors. But, there are more, but different, candidates for blocking!
Read about blocking on social networking here.