I still smell a rat. Perhaps they were not sent to spy but to lure. They use the encrypted police band radios and Glenn states in Chapter 19/2 11:20 that he has Police Radios. They could have been eaves dropping on them since Saul and Victor moved in with CJ. You might say, "Well, why didn't he hear them talking earlier when Michael asked him if he heard anything when he was at at the Colony?" The most likely reason would be that Dunbar had been overrun before Glenn was rescued by Saul or the Colony didn't have access to a Police Radio yet. This would mean that CJ wouldn't have had anyone to talk to therefore there would not have been any radio chatter coming from L.A. until AFTER Saul and Victor move in with her.
If Saul's voice is recognized and Scratch is still ape-shit over the the Tower folk then why not try to lure someone to the Colony instead of trying to find them in LA? Rough them up a bit, give them a peek at Lizzy. Tell them a few things about who Sean was, where he may have came from. Then let them escape. Also, Hope says that everyone knows how she became blind, so every knows about the Dunbar Tower and everyone knows that Sean was there. Glenn can put peices together easily, he's a smart ol dude.
Plus, It make no sense for Glenn to say, "I wasn't going to say anything but I can fix your Satellite Phone." Why WOULDN'T he say that? If he wants to get the heck out he would have blurted out, "Hey Saul, I can fix that!" Instead, he didn't even hear Saul mention the broken phone because he was gibbering on about Roman turing into a zombie.