@Always Eleven to him,
Oh, and why avoid passive? To avoid ambiguity.
I think that you're conflating two ideas from your grammar school days, AEtH. Can the passive cause ambiguity? Of course it can but it doesn't always and ambiguity, like so many other feelings/emotions, is, sometimes, precisely what a writer/speaker wants to portray.
What is language after all, but a medium that we use, and need to convey myriad nuances. The main job of modal verbs is to express ambiguity, doubt, indecision, ... .
Teachers who had no knowledge of the grammar of English were fond of emphasizing empty platitudes. How else could these things have
perpetuated themselves for so many centuries?
[I could just as easily have used a passive construction for the last sentence]
By myself can mean I wrote it, or it can mean I wrote it without help. Why have the reader scratch his or her head when you can be clear?
Virtually every collocation/lexical bundle/question/response used in English can have different, sometimes opposite meanings.
'yeah, right'/'unhuh' are two examples that can be negatives or emphatic positives.
Language doesn't operate in semantic vacuums. Noting that confusion can
exist is an old trick that comes from teachers hoping to forestall any real questions from students about language.
The piece, written by myself, was a fairy play in three acts.