This is a bad excuse and a wrong assumption.
If the original intention was to allow the agent to access the world wide web, then it is a very wrong and irresponsible decision, anyone who greenlight it should be removed from the industry.
Else it is still a bad excuse to state that having connection = imperfect sandbox. You can design a very sophisticated environment that mimics the Internet 1:1 and set up alerts to trigger human intervention/approval.
I'm not disagreeing, but you do know that's almost the entire industry?