If this event was fair:
Given say an average 120 total plates each player gain throughout the whole event (note we are not there yet, so those numbers would have to be adjusted, the left over amount would be roughly 2/3 of those)
The average player will complete no more than 15 sets, therefore having 30 left over.
Roughly one in 8 players will complete 12 sets or less, therefore having 48 left over.
Roughly one in 125 players will complete 8 sets or less, therefore having 72 left over.
Roughly one in 5000 players will complete 4 sets or less, therefore having 96 left over.

Given that, what have been posted could very well be the result of normal and fair RNG.
Large data would need to be collected to be certain, but given that many people would probably complain if they run into the 125, given the small number of complains I see every time this event come around, I'd see it's probably not rigged against us. It could potentially be rigged FOR us, thou I have no idea how that would be.