I, for one, see a discount code as another thing entirely.
I see handing out the code as "quid pro quo" for a company sending me free product.
Here's what I mean by this...
Someone sends me free product to review. In doing so they have to be aware that I am not going to give a biased review just because I got some free stuff...Never going to happen. I've also stated publicly that I would out anyone who even HINTED at wanting me to sway a review for them.
So, they send me free product and I review it. I now have a bunch of product left over so in essence the supplier has done me a solid by "hooking me up" with a bunch of juice.
By giving out a discount code and driving a little bit of business their way, I'm returning the favor in a manner that's unbiased and not liable to sway public opinion about a product. So here's what's happened.
Supplier does me a solid by sending me some product
I review that product and post an objective review...good bad or indifferent
I then do the supplier a solid by affording them the chance of doing a bit extra business...NOT by being dishonest in a review but by saying "if you decide to buy this product, after I've reviewed it, here's a way you can get a little break on the price".
I would include discount codes on products I gave negative
reviews to, just as quickly as I would ones that I gave positive
reviews to.
Discount codes aren't a manner of making a profit or of getting free stuff. They're a way of helping the community and the suppliers at the same time without having to resort to compromising our integrity to do so.
EDIT : I should say that discount codes aren't a way of getting free stuff
FOR ME. I have some discount programs in the works and one that's in full swing but NONE of them include anything about me getting free stuff and never will.
I will NEVER take free product in return for anything but a fair, unbiased, objective review.