Noone's buying 500 headphones just to return them a money back guarantee.
The only issue you'll have is people abusing the crap out of stuff and expecting a money back guarantee.
One is legal, the other one is a crime for starters. Morally it feels fairly different too.
They wrote back to me saying, "Don't worry, the glue is edible." Ok cool. I don't want to eat the "glue", but I think they missed my point. So I reply suggesting people probably don't want to eat the glue so they should fix the production issue to improve the quality of their product, even if it's just aesthetic. They wrote back asking how much free product would make me happy. None. I didn't want anything for free, I just wanted to make them aware of the problem. But they're operating on the assumption that everyone who complains is a bad actor who wants something for free.
But sometimes a money back guarantee is just a good channel to get valuable feedback, if you're willing to accept it.
I had a problem with a meal, something minor like an over cooked egg. When I returned it the manager said “Thanks so much for telling me. I will go make sure they do the next one right. And of course here’s a replacement.”
It really stood out to me because of the thank you, not for the replacement meal. Attitude is everything!
If you are working in customer support for a company that won't fix problems, a user telling you about a problem is just another problem.
Often customer support really really know about the problem, they just can't do anything much about it...
You'd be surprised how often that is true.
Most companies are willing to send free stuff in order to improve your mental image of their product or service.
What does improve my image of them is if they acknowledge the problem, treat it (and me) seriously, and make a credible-sounding promise that they'll fix the problem in the future. If all that's done, giving me a refund or replacement will further enhance the company in my eyes, but if it feels like they're just buying me off, it doesn't.
Companies hate the bad rep for chargebacks.
Most companies would rather refund your money with no questions than deal with the wrath of credit card companies.
Personally, in my own purchasing decisions, warranties mean nothing to me (They're a huge hassle, and I've never had an experience with warranties that didn't make me feel like I've been ripped off) -- but money back guarantees mean a huge amount.
Buying something without trying it first is a very risky thing to do. A money-back guarantee (particularly a no-questions-asked one) removes that risk from me and makes it much more likely that I'll take a chance on a product.
The other thing is that tests have proven people trust more if you offer a warranty or even a money-back warranty.
Skullcandy headphones are a great example, they're budget headphones that are nothing out there, a little pricy but they have a lifetime warranty. What's a lifetime warranty? They'll replace them as long as you are alive.