Absolutely - but it will be interesting to see what the defence argument is. A class action requires a unified approach [ argument ] and the defense usually requires some consensus in the response argument [ amongst competitors ].
It looks to me like a simple case of "they didn't pay the tax on the commission component".
But it will be interesting to see how the defence defines their business to try and get around it. They must have all acted on some pretty powerful advice from attorney's and accountants. No business likes exposure that can be clawed back.