Gear warnings

I have paid out of my pocket for several gear up landings by renter
pilots. I know they have the best intent. Rather than require more
insurance, I would prefer a better warning system.
Since I can not hear most warning horns (old ears) I would like to
have a stick vibrator, ( maybe that is off the shelf) a big flashing
light or an explosion. My wallet hurts, and teaching USTALL doesn't
seem to work.
Of all the students I have personally taught, I am the first...Yea,
Me. I landed on the belly while my passenger was having a panic
attack. Maybe the explosion would have gotten my attention.
For me, this is a serious request. Air brake handle markers have been
tried, but the renter pilot seems to forget to install them.
Please also tell me how to get my instructors to teach traffic
scanning. A friend and I had to take a shower and clean up both seats
yesterday. Four eyes, both activically scanning, gave a brief moment
that allowed a close encounter rather than planting a lot of glass
below.
They are very nice people and I love them, so maybe some words to me
would help keep my friends and me both flying.
Fred R.