They are in Cook County. That is fact.
Cook County law does say that nobody can sell hi cap mags.
That has been law for a while.
They have been selling hi cap mags since then.
So they probably have been breaking the law, until recent events got them noticed by someone at the county, they got a visit and a warning.

That was my point

Perhaps the law stated that they could continue to sell old stock, and they stocked up a few years worth of magazines?

Though, timing is suspicious...