> Are speed limits on private property enforceable?

I don’t think this is relevant to mapping the ground truth. It’s a sign that exists in the world that is obeyed regardless of whether it’s enforceable or not. If enforceability is a topic of concern, perhaps there’s additional tagging to be added (not in lieu) to fit your needs.

> If you want, you can add a fixme to the aisles and service roads in questions

Fixme tags are the burial ground of issues that then become not as easily discoverable and then are effectively swept under the rug and forgotten about. This is not a suitable candidate for a fixme tag.

Please don’t migrate issue from notes to fixme tags. This defeats the purpose of having notes for situations where it is affecting a collection of unrelated map elements.