DQ IX selling another million in second week?

[Viper1]

wenlan said:

2nd week over 1 million is not gonna happen for DQIX.
The 2nd hand market is huge in Japan, and those numbers won't be tracked.

A lot of core gamers finished this game in 2 days, if they don't care about the side quests, they will dump the used copies to the market.
Releasing games on DS has no mechanism (e.g. DLC) to keep gamers holding this game a little bit longer.

Still, SE has done a great job shipping more than 3 million copies to stores for the launch day.

Isn't the second hand market illegal in Japan?

Or was that once upon a time?