Our '97 has survived so far sans a belly pan, but once a piece of shale lying in roadway in a dark shadow (I was leading group, bright exceptionally clear day, harsh shadows) was clipped by the front tire enough to cut the tire (not through cord, but raised a bruise on tire on left side) and stand the shale up edgewise (I guess) and it got caught by the lower front cowl, it wrecked lower cowl and wrinkled the left side lower exhaust cover, missed the shifter though … could have been worse.
Those 3/16 rivets are where I had added reinforcement years earlier to back side of cowl at mount points as there was a crack in that area on other side. I have a nice piece of 1/4" aluminum, saving it to make a belly pan one day. As it was, was able to finish ride and found replacement parts that night from a salvage yard in Fla. Paint even matched. A pan maybe wouldn't prevent this, but it might prevent a hole under transmission.
Best plan … don't hit stuff.
Friend was loading his trike on trailer and caught trailer frame with his trike's transmission & cracked it …. oil leaked … his insurance co paid for repairs (replaced his engine & trans from salvage I think).