Last week I received a sizable shipment of mostly old sets from Bricklink sellers and filmed the live openings of four packages:
Notice the big box had questionable packaging, and I noticed a few small pieces were rattling around in the bottom of the box. What I didn't realize until a few minutes after this video was that an entire side of the bottom of that box was completely open, allowing parts to freely spill out wherever the package happened to be at a given moment. Expecting the worst, I tried assembling the set. I was not able to start step 1 of the instructions -- six out of the first seven parts were missing.
Over the next couple of days I treated a bunch of sets from an earlier large haul from a different seller and began assembling them. Here the packaging was fine, yet the order was not. Set after set had part substitutions & outright absences. I've encountered issues like these in the past, and I usually am able to fill voids with spare parts on hand, but the problem has gotten progressively worse, and worse, and worse. It's widespread. I've had missing, blatantly wrong, or misrepresented parts from probably 1 out of every 3 Bricklink & eBay sellers from whom I've purchased used sets. I'm talking experienced sellers who've been doing it for years and have thousands of positive feedback ratings. Sellers from the US, Canada, Germany, The Netherlands, the UK, and Hong Kong. Sellers who have no excuse to include one extra 1x2 brick, but miss a seat, two plates, and an antenna, and substitute trans-neon greenish-yellow for trans-yellow and trans-red for trans-blue. Sellers who know better than to throw parts in a sandwich bag and then into an oversized box with just a couple used produce bags as "padding." Sellers who should always tape not only the top, but the bottom of a box filled with $200 worth of vintage collectibles.
An occasional mix-up is only human. This is not an occasional thing, at least not any more. This is rampant. I've held my tongue probably longer than I should have, but now it's time to get the discussion going out in the open. If you know any Bricklink/eBay used LEGO sellers, please share this with them. If you have experienced wrong or missing parts in an order, please talk to your sellers and make sure they know they messed up, and it's not okay.