BEagle, glad we agree about something. IMOH You cannot check too often that your aircraft is ready to make contact with the ground, I would not discourage anyone from doing as many 'Final' checks as they saw fit.
Personally, I check about three times on final approach that the gear is down and locked, even when I'm not flying a retractable! The only thing which makes one look more of a prat than landing with the wheels up is running out of petrol. There is a certain CAA FE who would vouch for that (twice!)
Capt Homesick, If you teach (on a C152) that your student should 'ALWAYS' advance the throttle with their thumb stuck out then, sure as eggs is eggs, one day they will do it in an aircraft where their thumb will contact the 'Gear Up' button. Never, ever, ever teach a student to 'ALWAYS' do anything. Teach your students to 'UNDERSTAND' their aeroplane and it's systems, whatever type it may be.
Many years ago a good friend of mine advanced the throttle with his left index finger 'stuck out'. He spread himself and his jet all over the airfield at Mona. Just before Christmas as well! I later watched him fly a Sea Jet the length of the main runway at Culdrose at 30 feet, inverted - Wow!