Alfie took off the charm that was meant to alert Julien if he was in danger and left it lying under his pillow. He was sorry that he couldn't wear it. He hated lying to Julien about wearing it all the time. But the last thing he wanted to Julien showing up with Goyle was beating him up or something. He couldn't have stood it if Julien got hurt because of him or something.
So he left it, and shoved Goyle's essay into his satchel before making his way to the place he was supposed to meet him. He dragged his feet though, not rushing. He wasn't exactly in a hurry to see Goyle again.