Bob - take another look at the examples, and look for where the "|" and "+" actually are. Right now, you're mixing them together, with + inside tagexpr, where it's not used, and | outside of a tagexpr, so that won't work either.
tagexpr (HasFeat.fTrippBite | (HasFeat.fComExpert & HasFeat.fImpTrip)] <> 0
|