What does it matter who's following these rules? Do you really care whether a senator has properly installed a [Chair (Overstuffed)] in their personal office rather than their front office?
I'd be more worried about the opposite phenomenon. The handbook is apparently used by the Senate Ethics Committee. I'd be worried that a giant book of rules about how exactly to obtain your parking pass or requisition an easel or how to arrange chairs in the rules committee room (note: actual examples) could easily be used as a weapon against individual senators by accusing them of "ethics violations".
Rule violations by senators are a tricky thing. Senators do not in fact serve at the pleasure of the Senate Ethics Committee. They're elected by the people of their state. The Constitution requires the Senate to make its own rules, but those rules are primarily for the orderly conduct of business in the Senate.