It's honestly pretty "normal" that even though boards are sold as "new" that you aren't actually getting any warranty. This is likely because the boards being sold by the sellers were already purchased once from SM by some random company, either the IT firm/other business that sold off the liquidated boards, or whoemever.
You guys are forgetting, these guys aren't really re-sellers, and, especially aren't authorized SM retailers(that's not to say they can't sell boards secondhand, though). While they both arguably and literally fall under the definition of being re-sellers, what most of these people are are asset liquidators. They get the gear super cheap via auction or some other channel where the gear first belonged to someone else and "recycle" it to new buyers in these markets.
The boards that DO have full warranty cost the MSRP and state "Full Mfg. WARRANTY!!!" in the listing title.
By the way, I got 5 of those X9DRD-7LN4F-JBOD for 210 each, but, it was a pain. I think I'm the first guy to have spotted them. As soon as the listing went up I sent an offer and then the next day called them directly asking about i/o shields. The first time the boards were listed they were 225 or 245 /ea FS, dont remember, so I offered 135 for 5. Called, guy said no way, might be able to do 190/ea...I was like okay that's cool. He came back and literally asked if I would pay shipping, I was just like, you're already saving yourself the 10% ebay fee from doing direct invoice lol. Anyway, guy came back and said they had i/o shields and heatsinks, next thing I know these things are going for 295/ea on ebay, now they're even higher, 327. So, I got 5 for a total of 1050, /w io shields, I'm not too concerned about the heatsinks because I literally just bought 10 better heatsinks and got 2 free. I find value in the fact that the board has onboard LSI 2308 in IT mode because it saves me from having to purchase another 5-6 H310 adapters to flash to IT mode.
Anyway, it's a little annoying how the price gets hiked from 225 to 327.