Well I remember in the past the voting was built in a way such that there were 5 suggested maps and players should pick a number between 1 to 5 which represents the map they want and then there was also a problem that the map number 1 was always selected.
So the staff team came with this idea to make first two options not selectable and making a break of 5 seconds before starting the vote so that players could know there is an upcoming vote but this as I see didn’t work too.
As a conclusion, I see that ther’s nothing that can be done to prevent players from picking a specific option always since they are picking like they are programmed to do so.