There should be very few cases in which an individual might confuse the en dash, colon, and semicolon because en dashes are just not used similarly. Em dashes would be more commonly mistakenly used, because they serve similar purposes in a sentence. Colons can create emphasis in a sentence, just like an em dash can. Semicolons are primarily used to connect two independent clauses, whilst colons connect an independent and dependent clause together. En dashes have nothing to do with emphasis and are used to show range, or connections or conflicts between words instead. So, confusing an en dash, colon, and semicolon is unlikely. Confusing an em dash, colon, and semicolon is very possible though.