By default, this service is run under sharepoint farm account, and results in a warning from SharePoint Health Analyzer.
You can certainly change it to run as a different managed account to suppress the warning, but you should be aware of its ramification: the managed account running this sandbox service will be granted some privileges similar to farm account, such as db_owner roles for all WSS Content databases! And this role won't be reversed on later service account changes. This certainly violate least privilege rule.
