The purpose of the EVENT_DISPLAY family is to draw some sprites over the screen at a specific situation.
For some events it's possible to prevent drawing hardcoded stuff, like hiding the status bar or the crosshair via setting the RETURN var to a non-zero value on exit of the correspond event. But it's not the case for this(EVENT_DISPLAYBONUSSCREEN) event.
These event can be used to collect information about the map or change it but it is advisable to not do it since it can cause the game to go out of sync in multiplayer mode. --Hunter_byte 14:33, 9 August 2008 (PDT)