The idea behind this is that a message could be seen as a sales tactic, whereas a simple request without text is perceived as less intrusive, so no one can read anything into the message or feel offended.
After 5 days, the invitation to connect is withdrawn.
⤴Why should you withdraw connection requests?
Here you can see who you have sent a request to and who still has one pending
⤴ https://www.linkedin.com/mynetwork/invitation-manager/sent/
Here you can see when contacts have accepted
⤴ https://www.linkedin.com/mynetwork/invite-connect/connections/
