What I would lean to if it were mine and wanted a quick-install/remove, would be to fashion a stainless Z bracket, and mount one to each upright. For on the back of the teak, fashion two U brackets that slip over the 2 Z brackets. Kinda like brackets that might hold one end of a saloon table to a bulkhead.
Kinda like these but not really (but similar mounting idea.) A narrower Z on the pedestal guard, and a U on the teak, not a complete clip like these
Come to think of it (I do this a lot AFTER opening my mouth) it could be made of just flat stock -- 1/8" thick x 1" wide (McMaster-Carr) - if you're handy with a hacksaw and file (or a dremel) and a drill.
The guard upright side being spaced away 1/8" from the tubing 1/8" using washers or a section of the stock underneath, and the U side spaced away from the teal 1/8" w/ washers or doubling up the stock. I could do a sketch.
kk