"Sorry I seem to have offended you, but that is basically the only way sellers can protect themselves on today's eBay."
Thanks, but no apology necessary -- not offended in the least

-- just pointing out that simply observing a Buyer has left a negative in the past without also checking to see if the negative-receiving seller is now NARU, and/or checking to see if the negative-receiving seller has now received bunches of additional negatives, does not simply "get rid of 'riff-raff' Buyers -- it may block bad Buyers from your auctions, but it also blocks good Buyers -- as a Buyer, it would not affect me one way or the other, as there is no shortage of good auctions from which to purchase on eBay -- I agree caution must be used by both Buyers and Sellers, and I check feedback on Sellers before bidding -- lots of negatives, and I'm hitting the back-button -- a negative or two received by a Seller over a several-year period, and I will double check what comments were listed by both Buyer and Seller before deciding whether to purchase or bid --
While I purchase quite a bit on eBay, if I am looking for anything ThinkPad, I am absolutely looking on the Forum first -- gladly pay a percentage higher price on our Forum because of the typically easy and honest transactions which occur daily here -- but if I find a deal I like on eBay, I do my homework and have made almost 100% positive transactions -- had bad outcomes a few times, but I could say the same for shopping at WalMart -- won't keep me from purchasing an item I want at a fair price.