Imagine if I set up a rival music merchandising company, but ordering from you supporting your business, when I should be dreaming up ways to destroy your business. You don't really help a competitor.
Firstly, lets forget LF, as we all no, there is A LOT more to them than selling blanks and selling designs to consumer...
But by your own set of "rules" I should not use Listawood should I? I use them as an example very loosely as they are a much bigger operation than I will ever be (or intend to be), but they are a trade only supplier just like me and I have no problem in purchasing my blanks from them as they offer an excellent price and service. They do not try and steal my customers so where would my problem be? Many of my customers know exactly who they are and just prefer me to deal with, I don't know whether it is price or something more likely that I am better looking

Either way, I am happy to purchase blanks from them even though they could be seen as a rival.
I see a big difference between the two. A trade supplier wants the best of both worlds, he either wants more margin on the stock he holds or he wants trade buyers to break the bulk of his inventory so he turns his money quicker. The same trade supplier sells at a price his trade customers cant compete at, unless they want a razor thin margin, thus subsidising his retail sales. If he wants to retail then by all means retail, but dont pose as a trade only distributor.
The photographer plays on the same terms as most of us do, in fact he needs to be a little more expensive to enhance his "arty" sales pitch, he isnt the same threat to other traders in the same way the trade wholesale supplier is. Now if a retailer wants to buy containers etc etc and work on a thinner margin , then thats his business, he isnt using other decorators to sustain his business model he stands on his own two feet. (BTW or her)
I take your point in paragraph one but I personally think it contradicts paragraph 2. The only difference is the size of the threat, a photographer is not a very big threat so is not considered a problem, but he is still doing exactly the same as a trade supplier. He (or she

) has purchased dye sub kit to produce mugs (for example) in house more than likely to increase sales and profit, so they have taken that service away from a dye sublimation specialist, the same could be said for a screen printer - we have all seen the "I am a screen printer who wants to branch out" posts, is that not the same thing as a supplier of blanks saying, hey you can buy your blanks from me or you can get me to drop ship them. Like I say, I have a real problem with those that steal designs or copy copyrighted images (I still remember the member that claimed he had permission direct from an artist on here, that was until I pointed out he had been dead for 25 years...), that is a big no no and likewise if I chose a drop shipping service who started contacting my customers direct then all hell would break loose. But I genuinely can not see the issue. If you like the price they sell the blanks at then great, if you don't then get them elsewhere.
USING: Whatever it takes to get the job done...