Hi,

Under certain circumstances, it's possible to bypass the validation of being mandatory to have approval users/groups on approve events.

Steps:

• Create a new workflow
• Add an Event/Approve event
  On Users who approve content (or "Groups who approve content"), click "Add users" button (or "Add groups" button)
  don't choose any user. just click "Select" or "Cancel" button
• Save your workflow

After the steps described above, any new workflow bypass the users/group validation

NOTE: This was discovered while testing EZP-22372, but existed before the EZP-22372 fix.