Unopened mint sets too?

I just read the guide Unopened mint sets? and have to add a perspective. I have bought over 2000 mint sealed proof sets. I have opened about 1000. I also started selling these sealed proof sets in May 2006. I have to agree that the sets were not sealed by the mint. It just makes sense. If in 1961 I paid for a proof set I sure would want to see it to make sure I received the correct proof set!
So how does one acquire a seled set? The easiest way to find one is to buy a mint sealed shipping box of proof sets. The shipped sets gee in quantities of 100, 75, 50, and all the way done to a single proof set. Obviously the single set was just shipped in the envelope with an address on it. Was it shipped unsealed? Anyway, humidity is the main reason why the sets that are around for over 40 years begee sealed. Alas, there are unscrupulous sellers on okay. They are not limited to selling coins. I have bought some sets that seemed to have pristine envelopes and have proof sets that looked like they were stored under water. So sometimes one may find a set that appears to be resealed.
I take umbrage with the other writer. I sell unopened proof sets and I don't seal any. I purchased and opened a 25 count 1961 proof set box sealed from the mint from someone I believed was honest. Everyone of those proof sets had the envelopes sealed. Everyone had a cameo proof Franklin half. It seemed each coin was minted one right after the other. The quarters all had distinctive markings on the left eagles wing on the reverse. By the way each of the Franklin halves had a few spots on them and thus not of the proof 68 caliber. Yet they have beautiful contrast and truly are cameos.
I havebid and won auctions ofwhat the other writer would suspect to be resealed proof sets. They were coated with grime, spots, and some were toned. A few coins had cameos. One of the sets had a new envelope. One obviouslyprinted in the last few years. I opened them so I couldn't return them according to the auction agreement. I contacted the seller and he apologized. Told me he indeed would provide a full refund. However, I didn't want to have to ship and wait for a refund. I suggested he lower the price and give me a partial refund. He did and we both were happy. Some people like toned coins. Sell them on okay!
Watch out for bad/dishonest sellers. Buy from someone you have previously had a good experience. This means you have to buy the first unopened set and go from there. Use the feedback system. Readthe seller'sfeedback from buyers and sellers. Make contact with the seller. Ask questions before you buy.
What I presented was just anecdotal evidence. I have purchased coins that looked beautiful in the photo only to find out the coin wasn't the deep cameo that was listed in the auction. Photos can be enhanced! So unless you hold it in your hands you are not as the writer said "Personally I'd much rather buy a nice well preserved set that can be viewed before purchase and any defects disclosed."
Hope this helps too! And enjoy the coins you purchase.