Anonymized traffic may be in corporate networks well before the enterprise is aware. Anonymizers can evade corporate firewalls and Acceptable Use Policies, which defeats efforts to stop employees from accessing sites, webmail accounts, instant messaging and other applications that have the potential to open backdoors for hackers and malicious traffic to enter the organization. Companies need the right tools to gain full visibility into their networks. At the same time, organizations must work together with employees to set the right policies that balance user needs against potential risks.”]
Source: https://informationsecuritybuzz.com/articles/lifting-the-veil-on-anonymized-employee-traffic/