the fields like --cc are fine for simple stuff, but as soon as you want to perform a search for say "all bugs with sh@g.o or arm@g.o in cc", the current bugz code cant cope i wouldnt mind simply changing the emailtype1/emailtype2 fields from 'substring' to 'regexp', but i imagine others might get annoyed. so perhaps an alternative would be to add a --regexp option that would make all searches regexp based. this would allow the basic search (summary/etc...) to also use regexps.
Web services clients do not have any control over how fields are matched. This would have to be an enhancement to Bugzilla.
I am marking this invalid due to comment #1. It is an issue with bugzilla.