[plt-scheme] Does anyone use `set!' and `get!' patterns?

Currently, "plt-match.ss" and scheme/match (in v4) provide `set!' and
`get!' patterns, which bind mutators and accessors for the matched
locations, respectively. While these look clever, they complicated the
implementation of match, and don't seem to be used.  In particular,
I've searched the entire collections hierarchy, and they don't seem to
be used at all.  Given this, I'd like to remove the implementations.
Does anyone else use them in their code, or have any reason that they
would want to?

Thanks,
-- 
sam th
samth at ccs.neu.edu