See section 10.0 of the manual. Items that are truly "Fragile" require special handling, which has a fee of $9.95. Items you call "fragile" that are not really fragile do not need this extra fee - but if you want it to have special handling you pay extra.

Marking an item "fragile" has no consequence at the post office. They do not assign it to a machine that crushes it less, or a truck with extra padding. Marking it "special handling - fragile" means it will be treated differently, and you will be charged accordingly.

Marking a package "fragile" and not paying the extra charge means nothing to the post office - it's like marking the package "deliver quickly." The magic words "special handling - fragile" do mean something to them, just like "express mail" does. If you send a package with those magic words and do not pay the extra charge, they will either send the package back to you for additional postage or deliver it to the recipient with a postage due notice. (in other words, don't use those magic words unless you are prepared to pay the fee)

When a desk clerk asks you if there is anything fragile, the answer should be "no" unless you want to pay extra. If you want it hand canceled, just say so. Calling it "fragile" only leads to confusion, and that confusion is avoidable.