Restrict Closing of Shop Order operations

Operations are typically automatically closed. This option is basically just used when overriding the normal close. I.e., closing an operation before full quantity is reported, or keeping a fully reported operation open.

You can anyway try to configure this assistant using page designer to hide this setting for the operator. 

Setting up dummy work guidelines , adding a competency profile for signoff , signoff required to close operation options can be used to restrict employees from closing operations.

But it will result in some additional work to sign off the dummy work guidelines.