>>513466922
Because they will find a way to fuck you over for it

A disabled guy i know bought an 1969 Opel GT, a wreck of a car to do a little work on now and then just to have something to do
Close to ten years later it was completely restored back to original, so he called for an insurance appraisal again just to be on the safe side
They said it would be worth upwards of 70k and being the upright honest citizen he was, he said so when it was time to file the tax returns
Result was that he lost disability for being "able to work" was fined for not telling he "was working" and had to pay 38% of the 70k estimated value in extra tax because that put him over the limit on what you are allowed to earn while on disability, which he did not have so he had to sell it, but the market was so slow that Kemneren (Norwegian IRS) took possession of it and sold it for peanuts to cover unpaid taxes and fines