Correcting the reviewer.
Notes: “should of” isn’t valid, should implies a verb, of isn’t a verb. I expect you meant “should have”. Please recall this in future submissions.
They should of course keep that in mind, but it’s not that “should” should always be followed by a verb directly. The problem is that “of” in this context is a mishearing/spelling of “have”, so they should in this case have written it like that instead.
I would argue that “should of” is just a naive written rendition of the spoken contraction “should’ve”. They are homophones, so it’s a completely understandable error among those without the relevant education or background. I know only English and was in Grade 9 at a different school before someone corrected me.
should implies a verb, of isn’t a verb
“should” and “of” should probably be in quotes here?
A question mark does not fit the sentence, which is a statement (“they should.” rather than “should they?”). While question marks are commonly used to demonstrate a rising tone at the end of a sentence, its not considered correct for formal writing.
A-ha, but this most decidedly not formal writing! UNO REVERSE CARD.
But on a more serious note, I did intend it as a sort of question because I’m not 100% sure, because the rules for quote use might well be different in English than my native language. I actually also don’t know the rule for question mark usage in English; is it generally considered a crime against orthography to plonk a question mark on something that’s a statement, or is it valid in some cases?