I agree that Arrow's Theorem is often misread (as it doesn't apply to score-based voting systems, or single-winner elections) but it's perhaps more important to

I agree that Arrow's Theorem is often misread (as it doesn't apply to score-based voting systems, or single-winner elections) but it's perhaps more important to mention the Gibbard–Satterthwaite theorem here, which is similarly misrepresented. That theorem effectively says that all sensible voting systems will in certain conditions allow a voter to gain a better outcome by voting insincerely (i.e. tactically). However, it doesn't say how easy it is for a voter to determine the correct tactical vote to make, so potentially a voter would need perfect information about all the other votes cast in order for their tactic to succeed.