For a start, it is nearly obvious that Jesus wasn't born there at all, and that they have to convince themselves and the public that this form of 'lying for Jesus' is not a sin.
But the different denominations have also had to cooperate with each other to keep the place clean, and apparently the rights to clean particular areas are jealously guarded.
It seems that they have failed to maintain their composure this week. Armed with brooms the clergy of the Armenian and Orthodox movements have had a pitched battle.
What a way to behave in front of the public! Apparently injuries were 'slight.