I think it's nice to have the reserved parameters list in the spec. Assuming that
component documentation will soon be auto-generated, who will then users know which
parameters are simply not allowed?
On the other hand, I find more interesting exactly the opposite functionality:
an IMarkupWriter that aggregates values for the same parameter name.
Components that are decorated by ValidationDelegates can then solve issues like
TAPESTRY-975 - those components could (conditionally ?) use this new (and a bit more