@MariaAbrahms I think what @lvh suggests about not passed (instead of using the word null) makes sense.

Right now, this is how it works:

# servers in group?  | force value    | what happens
-------------------- | -------------- | --------------------------------
Yes                  | true/True/tRuE | group deletes, and all servers
Yes                  | not given      | 403 - GroupNotEmptyError
Yes                  | anything else  | 400 - InvalidQueryArgument
No                   | anything else  | 400 - INvalidQueryArgument
No                   | not given      | group deletes
No                   | true/True/tRuE | group deletes

We may want to change it so that false behaves the same as not given.  So I wasn't sure if you wanted to change the doc to behave how it CURRENTLY does, or if you wanted to leave it as "false or not given" because we can file that bug and fix it.