Granted, I'm no legal expert. Take what I'm about to tell you with a grain of salt. If you want a more definitive answer, please consult a lawyer.
The law actually says very little about used software. However, you could still receive a fine or other serious penalty.
How does that happen? Is there a way around it?
Used software technically falls under a copyright rule more than a century old. It's been used to fine used-software sellers in the past.
I'm talking about the First-Sale doctrine. Originally, it dealt with used books, but it still shows up in cases.
The logic isn't hard to follow. For example, you can't make digital copies of a CD and then sell the CD. That makes sense, right?