Ohio Rev. Code § 3.34
All official bonds; bonds of executors, administrators, guardians, and trustees; bonds required or authorized to be taken by or before a court, judge, or public board or officer, judicial or ministerial; bonds of indemnity; and all other bonds conditioned to become void upon the performance by any of the parties thereto of the stipulations contained in such bonds shall bind and render liable thereon both principals and sureties, whether at the time of the signing of the bonds by any of such obligors the amounts of such bonds are filled in or left in blank, if such amounts are filled in before or at the time of the approval or acceptance of such bonds. Such filling in may be done in the absence of any of the obligors, and without any express authority for that purpose from any of them.
R.C. §3.34