C95J said:
If I saw a piece of a fallen satellite in my back garden, I would definitely keep it, sorry NASA.
The reason they say not to touch the debris is because satellites often contain toxic, sometimes radioactive materials, and collecting, showing off, or selling this kind of thing can lead to a lot of people getting sick or killed. It can also, in the case of components that are intentionally sent back to earth, lead to a waste of tens of millions of taxpayer dollars and years of work when data is destroyed or samples are contaminated.
When NASA says do not touch, it is generally for a good reason. At least, they are far better reasons than any you could give for ignoring them.