Graham,
In response to your question, NO, I'm not taking the pi**. If you're not aware how walking on carpet can, and will transform a rubber backed underlay to powder over the years, might I suggest this has just been a learning curve for you. Likewise, trainers are the worse things to rip up the pile on all carpets.
I'm only trying to help someone that might have overlooked the fact that when he walks around his home, dust appears constantly. Carpet underlay seem one logical solution. It may not be the right one, but a simple check could rule it out.
If you are curious to know how I came to this possible conclusion, I phoned my uncle to ask him the question and he offered me his 35years worth of carpet fitting experience.
Climb down out of your tree and respect other forum members before handing out 'bitch slaps'