There are a few things to take into consideration when thinking about turning off all outbound scanning:
1) Signatures - the GWAVA 4 signature feature will not work if outbound scanning is disabled
2) Outbound Learning - if you are using GWAVA 4's learning features, we recommend using outbound messages as a source for ham (see Non Spam Autolearn page of GWAVA 4 Management Console). This will not work if outbound scanning is disabled
3) Internal users' outbound mail will not be scanned for viruses, spam, content, etc.
To avoid the previous issues, you may want to consider disabling outbound scanning for spam only. Here is an article that shows you where to change the two methods for disabling outbound scanning in GWAVA: https://support.microfocus.com/kb/doc.php?id=7020490
See also this related article: