Over the years I've done a fair amount of reworking documents from "he or she" style to "they" style. I've found that using "they" style does quite often make

Over the years I've done a fair amount of reworking documents from "he or she" style to "they" style. I've found that using "they" style does quite often make it harder to be clear, when you've got a sentence that's talking about both a person and some things. Something like "Then the operator must update all the rules. They must ensure that no bad things happen." Does the "they" refer to the operator or the rules? Of course you can always rephrase to make it clear again, but you're losing a certain amount of freedom of arrangement that you might have wanted to use for other purposes.