FBO Insurance requirement for tie-downs

A local FBO has the following requirement in its contract to rent
tie-down space. I would like to solicit opinions on who thinks this is
a reasonable request and why? My take is the FBO should have its own
insurance and not rely on mine for anything.

Besides the general requirement of proving you have insurance on the
aircraft the following is also listed:

"All such insurance shall name the Landlord (FBO Name) as an
additional insured, and shall be written by insurance companies have a
"Best" rating of A or better....."

I understand why the bank needs to be on the insurance paperwork but
why this?

Thanks,
CK