I can see your point of view Scott. However, where this might not suit you is if you sold a tenanted investment commercial property where you're the landlord and the new purchasing lessor wants to hold you over as guarantor until the end of the current 5 year lease in case the investment doesn't perform as well as you said.
Another example is where John the hairdresser trading as Snips rents the premises from you and sells the business to Peter who is a complete stranger to all parties. Normal everyday sale of a business. After John sells the business, he is most certainly not going to be willing to be guarantor for Peter. Also after John sells and collects his money at settlement, if he has to be guarantor for some stranger called Peter, then John's bank will downgrade John's borrowing capacity by the amount of his "liability" because he's a guarantor for someone.
Under the terms of most leases, depending on who writes them, assignment of the lease usually requires the approval of the landlord who cannot reasonably refuse. Usually the assignment clauses say the buyer must be of good character and have the financial standing and business skills to operate the business and pay the rent. It usually becomes the landlord's sole risk not shared with an outbound tenant.
So I'd have to say in my experience I think this kind of onerous holding over "guarantor for strangers" clause is uncommon and should be contestable, but I'm not a lawyer.