scot free vs Scott Free
Scot-free
To go scot-free (or to get off scot-free) is to get out of a situation, especially a legal one, without punishment or harm. The term tends to have negative connotations. We seldom use it when someone who is obviously innocent is cleared of charges. Instead, we use it when someone who is obviously guilty unjustly escapes punishment or does not face charges. For example, when a confessed bank-robber is cleared of charges on a technicality, we might say he got off scot-free. We probably wouldn’t say this of an accused bank-robber who is cleared of charges thanks to a squeaky-clean alibi and eyewitness testimony in his favor.
Scot-free is an old word. It derives from the Old English scotfre, which in Middle English became shot-free. The scot and shot in these old forms denoted a royal tax, so someone who was scotfre or shot-free was exempt from the tax. The modern sense, as well as the modern spelling, developed from these origins around the 16th century.
Because the scot in scot-free has nothing to do with Scotland or Scottish people or things,
it does not need to be capitalized.
https://grammarist.com/words/scot-free/