This script will let you look for the SCID/RID of any player by simply going to their Social Club Profile in the website.
- Install Tampermonkey on Chrome/Firefox.
- Click on the extension, go to Dashboard, click on the [+] button.
- Go to Installed scripts tab, enable the script.
- Go to the Social Club website and log in with your account.
- Find the user and go to the profile page.
- Refresh the website.
You'll find the SCID at the right side of the header.