How to block online path ? I dont know if there are update blocker on ubuntuOnly if you don't know what you're doing, or have no clue about IDUs in the first place. (There is a disclaimer within xyzz's installation app for a reason!)
If you leave wifi on without blocking online paths to update files, then you are making yourself prone to automatic updates without you even agreeing to licenses or being told that an update file is being downloaded in the first place.
tl;dr, use at your own risk, I guess...