not necessarily Momo has one of the best CoO out there. he can follow the haki.
i am betting Oda just used that to let the others see that there is another Dragon especially the CP0 will be funny if he went through the room they are in :D
i am betting Oda just used that to let the others see that there is another Dragon especially the CP0 will be funny if he went through the room they are in :D
In fact CoO is conceived as a sixth sense to begin with and it works on actual beings by sensing their presence and emotions.