xss query

[eluser]bgreene[/eluser]
using jquery to submit fielddata "bill's prog is in c++".
post data is fldx=bill's+prog+is+in+c++.
using $this->input->post('data', true) effectively screws up the plusplus at the end
by giving me "fldx=bill's+prog+is+in+c++" instead of "fldx=bill's+prog+is+in+c++"
am i doing something wrong or is this a minor bug in the xss unit or should xss filtering be the exception rather than the rule?
many thanks for a great system and superb support.
bill