So, in the most recent game I've run, the party encountered some malfunctioning cargo loading droids in the cargo bay of a Dreadnaught-class Heavy Cruiser. The droids were following their last command, which was to dump everything from the ship. So while these droids weren't programmed for combat, they were still trying to pick up the players and chuck them out the air lock. During the scuffle, one of my players had a bright idea. Disable one of the droids instead of destroying it, then reprogram it. Since we know droids can be reprogrammed to follow new masters (K-2SO), I allowed it without worrying about it too much (Just required a rather difficult computers check at the end of combat). After all, what game-breaking use could they possibly come up with for a cargo droid that wasn't programmed for combat?
My mistake was in underestimating the creativity of one of my players. The party has now decided to replace the head and torso of the cargo loader droid with an astromech socket, so that the party's astromech NPC will now have a mech suit. I'm totally going to allow it, because I think it's hilarious, and I can't wait to see what they do with M8-TY the Rustbeard in a mech suit.