Never. I literally buy everything from there, from dental floss to protein bars.... Endless to name it all really. I have made upwards 1000 purchases this year alone, and I have returned several items too (defective, broken, etc)
I believe it's really common sense. People DEMANDING discounts and price adjustments, and even returning defective crap and keeping a good item (defective bought somewhere else) and the best one of them all : my item never arrived.
Amazon is the best store on the planet, and people who take advantage of that amazing customer service SHOULD be banned.
You shouldn't have anything to worry about if your returns are legit. Promise.
In fact, I wish they were official SSC and HT distributors too.