My reports were filled with "May we please get an extra plate for the dinner scene?" and "Is it possible for Sara to have a purse at her entrance, please?" "It would be great if..." etc. As I have grown as a stage manager I think this approach for all of my notes makes it seem as if they weren't priorities and made me look like I was afraid to say what the productions needs are.
In addition to the concerns you bring up, this type of language also suggests that it isn't a requirement. "Is it possible for Sarah to have a purse at her entrance, please" gives people an avenue to say no. Of course it's possible, it's a purse; you're not asking them to re-design the set. This is one of the reasons I'm such an advocate of strong, decisive language. It's natural that most people will seek the path of least resistance when making a decision. If you give them an easy out, many will take it.
My more general thought on this is that your rehearsal and performance reports are archival notes of the production. They are formal documents and should contain simple, factual, neutral statements.
If you're worried about your report language or emails being interpreted as terse, develop a rapport with the related parties ahead of time. Grab a coffee, grab lunch, or have a phone chat if they're in another city. If the only way they know you is by your reports, they may think you're a jerk. If they know you otherwise they'll understand the voice with which you're authoring the language.