There is a “make private or public” option in the dialogue as I recall…but I saw that in the free browser version rather than the pro version you probably use. I’m sure the options are similar for commercial users.
You have indicated that you are using SU Make. You also identify yourself as representing a commercial business enterprise. This is a direct violation of the terms of the End User License Agreement to which you agreed when the software was downloaded.
SketchUp Pro must be used in this situation. Your use of SketchUp Make is illegal. You are required to only use SU Pro and for this reason it is requested that official licenses for SU Pro be purchased and installed for you and all of the salesmen representing your company.
This information is being provided to the SketchUp administrative group who will determine what legal action may be pursued.