If you see such a thing in use by an adult, I’d be surprised. It would totally throw off the balance point of the instrument in normal playing position. If played in a vertical position, the angle of the bocal would be wrong. I played bassoon from age 14 through college, and later had friends that were professional bassoon players in symphonies and classical ensembles - nary a peg in sight.
I took a look at the John Packer website to see if they offer a peg on their bassoons. Nothing in sight for a peg, but they do note accommodations for a seat strap.
JP291 Bassoon ABS Silver Plated Keys
jpmusicalinstruments.com
- The JP291 features:
Silver plated full size mechanism is modern, robust and offers durability
- Made from high grade ABS, the instrument is lightweight and mimics the tonal qualities of wood ensuring a warm, even tone
- Features a high D, Eb and E key for and large note range that can open up more repertoire opportunities
- Inclusion of 2 ring holes in the butt cap is ideal for use with a seat strap
- Hand rest and hand strap to increase playing comfort
- Right hand crook lock is also included