It might be nice to be able to have multiple onActivate( ) methods on a page, each handling a different number of context elements (including none).
Howard's comment on the mailing list (http://www.nabble.com/T5%3A-onActivate-error-handling--tf3281698.html):
"I'm thinking the change will be: a method will be invoked if the
context has at least as many values as the method has parameters, and
will silently skip those that request too many."