I see nothing wrong in an owner promoting his auction.
I am sure the OP is not the owner in this case, just speaking in general.
Well, it can been seen as a sly move if someone pretends not to be the owner, but I see no reason why someone should feel the need to hide that.
I think why some auctions “fly under the radar” is because they don’t have the means to advertise much, and why some owners give their watches to such auctions houses is because they don’t have the means to go to a bigger auction house. So hushing it up so it will go for cheaper though may be financially beneficial and satisfying, isn’t something that should be aggressively promoted especially in a well regarded forum like this.