Tbh you might be right
@Albino ๐
I mean it seems that hiding one presence is a CoO feat and Gaban who is as strong than Rayleigh and Roger was not seen as a threat(or with a strong Haki) by Luffy and Zoro so it might be because he is hiding his presence.
If the above is true Gaban being able to ยซ disappear ยป might make Luffy unable to see his future move with FS.