>>Anthon+Im1
The heated seat is an edge case, but there is also the entirely valid argument that you shouldn't be able to arbitrarily modify your car (e.g. replace the breaks with some home-grown solution), as it can put yourself and others in danger, and I see no evil in that being enforced by the government. A more IT-related example might be what radio frequencies can we use - if anyone could spam the whole spectrum, we would lose more than from the "freedom" of being able to do that.
So it's actually far from trivial to draw a line.