Just a quick reminder to scan your sealed games (backlog, sealed collection, whatever floats your boat) for potentially missing cartridges. Most of my collection I bought used, second hand, mostly from eBay - never a problem here. Out of roundabout 100 games I bought new and sealed over the years though, I've just recently discovered 2 that actually contained no cartridge at all.
First one was "Bayonetta Origins: Cereza and the Lost Demon". While going through my collection for organization, I noticed that the sealing foil had a tear that looked as if the foil had caught on some edge at a point and it was ripped horizontally (but very cleanly). The Nintendo sealing stripe was still intact though, so the game did not look like it was actually opened or even openable. Since the foil came very loose when I tried putting the game in a sleeve, I decided to take it off and found that it actually did not contain a cartridge at all.
I still have about 30 other sealed games in the backlog, so I was worried there might be more cases like that. After some trying and tinkering I realized that the answer to my problem was literally clear: The clear Switch 1 cases allow to shine a flashlight into the case from the bottom and you can see relatively clearly whether there is a cartridge in the holder or not. Lo and behold: I found another one in "Tactics Ogre Reborn" that seems to not contain a cartridge at all. The sealing foil (3rd party publisher game without a Nintendo stripe) looks perfectly fine at first glance and only with a lot of scrutiny you can notice that there is a tear going along the thin, opening side of the case and the foil can be pushed aside ever so slightly.
Ultimately that means I bought about 2% of empty cases over the years. Nothing to scoff at. Both of the respective games came shipped and sold by Amazon itself, no 3rd party dealer via Amazon (probably 90% of all new and sealed games bought through Amazon though, so the probability of the seller being Amazon was quite high...).
I tried the same method with Switch 2 cases too, and while it is a bit harder to see due to the red tint, it should work just as fine.
Have you found this to be a problem? Have you gone through your backlog and checked at some point?