I have a feeling that the rules for determining whether scale=T will be confusing for users. Right now, in `props()`, it depends on whether you use `=` (unscaled) or `~` (scaled), unless the item on the right is in a `prop()`, in which case it depends on either (A), the value of the `scaled` argument, or if that's not specified, (B) whether the thing inside `prop()` is a constant, expression, or delayed reactive.