Basically, there is always a risk of this if you buy from online, with a few caveats. Amazon and other big-box retailers stopped accepting returns of these products, which in theory should cut down on repacks -- but this is only true for the ones they sell; if an individual merchant sells their own secondhand, they may still be reseals. However, Jer isn't buying from these places, I think: he seems to be hunting for deals and low prices on Ebay, which all but guarantees you get reseals.
More importantly, though - it means Jer has no FLGS. That's shorthand for Friendly Local Game Store. If you have one even remotely close to you, you want to try to buy your product through them (when possible) because the people who run these stores always ensure that the product is good, not resealed, and as direct as it gets short of having a contact with a distributor. It's very uncommon for people to buy direct from product distributors, but almost everyone on the platform who does box openings buys those boxes from their LGS. You do pay a bit of a premium, but you're both supporting a local business (which also means a place to play pickup games)... and ensuring you get good product.
This tells me two things: he doesn't have the money on-hand to buy this shit at full-price; and he doesn't have an LGS that he's welcome or a regular at. Considering he tried to bill himself as a big deal in the MTG community, to where it was his whole thing before he monkeybranched to Sargon? It's really odd. I'm beginning to suspect he's developing (or has had) agoraphobia.
