I was originally going to post and say I would be upset with your sister for treating you this way. But after reading subsequent posts I have a feeling I see why she and the other baker lied to you about having copied your design.
And to answer the question, I'm complimented when I find a copy of one of my designs online and I even keep a file of photos of copies of my cakes.
Your exactly right....I am questioning the integrity of anyone who says it's ok to steal anothers' idea or design verbatim..... You do know that the word STEAL refers to illegal and morally wrongs acts, right?
AGAIN, inspiration is one thing....stealing someones' idea outright is morally wrong.....
So if you change one little thing then that's ok?
Obviously, I have dealt with brides of the same caliber as you have dealt with. When they bring me a photo of a cake they want replicated, here's what I tell them..."I won't copy that cake exactly the way it is. I will do something similar and I will make it better. One, because I don't agree with copying the work of another person and two, why would you want the same EXACT cake that another bride had? Don't you want something completely new and unique to YOUR wedding?"....and you know what, I lose maybe 5% of prospective brides that way but the other 95% understand and completely love my reasoning.... No need to compromise my morals just to satisfy the needs of some brides...
You can't make everything better. Do you see yourself as someone who can improve works of art like Vincent van Gogh's Starry Night? Is it immoral to have a print of it hanging in your house? What a sad world it would be if each lovely cake design could only be enjoyed once.
Rare is the caker who is truly an artist. I know of maybe 6-7 bakers in the country I'd refer to as true artists - people who are making original art in cake. There are some who are talented enough to say they are artists expressing themselves in cake. But I'd say 95% of us are what is referred to as artisans -- people engaging artistically in a craft, cake decorating. If your Facebook page is the one with the big pink Coach purse cake, I can't say I saw anything I would call art. And with the Coach purse on there, I am stunned you'd call someone who copied your work a thief.