A pilot wouldn't know there was no grease in the coupling
Your preflight inspection should include running your fingers around the rubber boot, checking for splits or grease.
I found one in '97 that was split in such a fashion, with attendant grease spattering around the Txmsn well, that needed a driveshaft change. Another good reason for always wiping any grease or mess with a rag during the preflight, because any new stuff will show up in the postflight.