If we enter (U+100000 , f4 80 80 80, <Plane 16 Private Use, First>) symbol in Web Scenario name, we get following error:

Error in query [UPDATE items SET key_='web.test.in[*,?,bps]' WHERE itemid='23509'] [Duplicate entry '10134-web.test.in[' for key 2]
SQL statement execution has failed "UPDATE items SET key_='web.test.in[*,?,bps]' WHERE itemid='23509'". [httpconf.php:227 ? CAPIObject->update() ? CAPIObject->__call() ? czbxrpc::call() ? czbxrpc::callAPI() ? call_user_func() ? CHttpTest->update() ? CHttpTestManager->persist() ? CHttpTestManager->save() ? CHttpTestManager->update() ? CHttpTestManager->updateStepsReal() ? DB::update() ? DB::exception() in C:\zabbix\ZBX-TRUNK\frontends\php\include\classes\db\DB.php:547]

Symbol replaced with *, becouse JIRA doesn't allow to store this symbol.

Symbol can be copied from: http://www.utf8-chartable.de/unicode-utf8-table.pl select dropdown last option.