Make them use the modeller to let them see how worse off they'll be.
Compared with what exactly?? And remember the modeller doesn't take into account any lump sum you will almost certainly take and so the headline figure of what it would cost you is higher than it would be in reality.
I have around 10 years to go and frankly have no idea what my pension will be based on at that stage. Will it be £50k more than now or £100k. So if I don't know how will someone with 30 years to go? All you can do is have a gut feel for where you think it could be.
Has anyone thought just how rises above RPI are going to be achievable in the long term without major changes to WP, leave, shift length? In my view unless we are prepared to sell these "high value crown jewels" then rises will be lucky to be above 0.5 above RPI anyway. So little or no change to most of us even in the medium to long term.