I won a fight with both a Myers sampling kit and a tome of binding equipped and got a digging claw but not Scraping Summons. As far as I can tell from the info on the wiki the digging claw drop does not require the sampling kit, but having one equipped still seems to override the tome result.
Edit: Did get the technique with just a tome equipped, but I also fed it a centipede from the choice encounter first. So it's not clear what the trigger is, or if it's just not a 100% chance to get the technique in the first place.
Edit 2: Did not drop any cooking ingredients with just a sampling kit and no tome, and a shiny butcher knife equipped.