A seat that is not held in place properly can be dangerous if not at least uncomfortable and annoying. Newer and better designs of the piston style seat post have minimized all forms of wiggle and seatposts with actual adjustable pistons built into the post are even available.
A seat that is not securely fastened can be hazardous if it is at least uncomfortable and bothersome. Modern and improved designs of the piston-style seat post have eliminated all forms of wobble and seatposts with actual adjustable pistons built into the post are even available.