Doesn't the advert say "paid cash for my car & didn't want to even take it for a test drive". Obviously that would be suspicious to anyone (or it should be). Who has honestly bought something 2nd hand off a complete stranger & never tested it to see if its working as it should? I bet not a single person in here. If you have then IMO you're a bit daft
As for the storing large amounts of "materials", the advert says "storing a large amount of chemicals".
Personally I think it's a great method of information gathering. I would rather the police investigated 100 innocent people (including myself or any family member) than not investigate 1 person who then packs the large amount of chemicals into the car they bought for cash without testing it & blowing myself or a loved on up.
What's more worrying to me is that every other advert is someone trying to offer a loan with 2000+% interest.
As for a terrorist not being clearly defined, how can you use one definition when you have Muslims trying to kill none Muslims, racists trying to kill black people, homophobes planting nail bombs to blow up gay people, Irish people trying to blow up none-Irish people.
I think the term covers such a broad spectrum precisely because the activities of various people covers such a broad spectrum.
Just my 2 penny's worth