Bingo Robin Hood Bingo Changes Contribution to Progressive Jackpots

Hi Bingo Balls,

I received the following email from Robin Hood Bingo:

We would like to inform you of certain changes to our Terms and Conditions. Please note that starting 01/02/2016, on some progressive slots games, only wagers made with real money shall increase jackpot prizes, any wagers made with bonus funds (including restricted winnings from such funds) or free spins, will have no effect on the jackpot prize amount.

You can view the updated terms by clicking here.
Your continued use of our services after 01/02/2016, will be deemed as acceptance of the updated terms.

First of all when I looked at their T&C's today, they were last updated in December 2015 with no mention of this rule for progressive jackpots, at least none that I can find. Did anyone receive this email from other Cassava Enterprises/Dragonfish sites?

If bingo progressives are based on ticket sales I suppose this seems fair, right? Tickets bought with free money are technically not ticket sales, or are they? I looked at two major bingo sites, Gala Bingo and Mecca Bingo, and could not find anything in their T&C's that describes the contribution to progressive jackpots.

I guess this applies to both bingo and slot progressives. What do you think, fair or not?

Source.