I don't believe a lot of them are real.
And no, I won't call out any one specific group because there are actually multiple groups from multiple companies I think are purposely inflating sales.
And yes, I know Gaon had put out a response to this but tbh I really didn't take their response seriously because the truth of the matter is that where there is a will, there is a way. People (and large companies especially) can always find loopholes or ways to cheat the system. No system is 100% infallible.
And honestly, I think it's easier for companies to rig album sales than it is for digital streams. For example, there is nothing stopping big companies from sending money to overseas retailers where they can't be tracked and make those retailers buy their group's albums. This will inflate Gaon numbers but will result in low Hanteo numbers because really fans aren't actually purchasing the albums and they just sit there to collect dust. Who is the album police that is going to investigate them? Who can prove that these "overseas undocumented" retailers are real or not?
This isn't 2012 anymore. Most overseas retail stores are Hanteo certified so there really shouldn't be over more than a 200k difference between Hanteo and Gaon.
Anyways, that's all I gotta say.