I very much doubt it. If they try and pull that on you i would be going to AFCA.May not be the right place to ask but it is related still so i'll throw it out there.
I applied for the Virgin Money Flyer card and have been approved today. However i only noticed today that NAB is likely to have approval by June 1st to buy Virgin Money. I had a NAB card up until a few months ago though, is that likely to affect getting the signup or bonus points? I would be disappointed if so! Partly my fault for not checking though..
Even if NAB phase out Virgin money cards eventually you have an agreement at the date you get the card and associated conditions required to get the bonus.