one can watermark (and copyright) their own photo without using a website reference that advertises a commercial product.
i do it all the time, but sometimes forget here
as i do not object to fair use of my photos here, but would object to their commercial usage.
for example: see my smart weapon photo attached.
p.s. remember the first rule is 'the moderators are always right'. the second rule is 'when in doubt, refer to rule one'.