I've gotten conflicting information in the past on this. One is that these are being provided by a distributor that MLS is on good terms with but warranty has to be handled by sending back to Longmont which in turn sends it to the distributor who handles matters. The other is that these are indeed legit sales and you can get warranty outside of Longmont. The way the second story is that Denon really doesn't care how their receivers are sold but they don't want it known that there are some people who will sell a fully warrantied at prices below what their published authorized resellers will.
I have no idea what famous brands, other than Denon are being talked about. Myself, I'd contact the manufacturer and pose the question and use their response to guide me accordingly.
Well it's funny.... Based on their post of a msrp of $1500 and on the asumption that's denon I'd assume that this is a denon 3810ci.
This particular part is available from reputable sellers at around $945 NIB and $650 refurbished according to google products. Av123 is selling a greymarket condition unknown unit for bundled for a price of $1000. Anyone thinking of buying this would be wise to consider that they can do better from an authorized dealer after about 20 seconds of research.
If they are getting it from a distributor and they are not an authorized reseller this might impact the length of coverage. Often this is based on the date of sale from the distributor not based on when this is bought from the suplier (in this case av123). Also if av123 needs to be involved in an rma or a repair request what happens when they are out of business?
I don't think anyone is recomending buying anything from av123... The advice isn't piss poor, it's just advising people av123 is being sketchy as hell about another issue. If a buyer actually contacted denon it's probable they wouldn't be told that av123 is a reputable dealer or an authorized reseller.... This is just another reason not to buy from, rather than something to check before buying from them.