The other week we learned that those who wanted to pirate games for the Switch 2 were in for an unpleasant surprise. Apparently, the Switch 2 can detect and identify if you are using so-called MIG cartridges for piracy, which means that the console is immediately banned from online use.
That's probably pretty reasonable to most people, but there are consequences that affect even honest customers. My Nintendo News reports that customers who bought a returned Switch 2 at Walmart made an unpleasant discovery... The consoles had been banned from online use due to piracy. But since it's not visible on the device itself otherwise, they've been taken back by the store.
The bottom line is, be careful when you buy Switch 2 used. Chances are you'll get a console that's functional in every way and in great condition - but can never go online.