Disable automatic installation of Teams - It should be an opt-in service, rather than being forced upon users.
Andrew Chandler commented
I think a smarter idea would be to do exactly the same behavior that Lync and Skype for Business did... Install it, but DO NOT auto-start until the user opens the application for the first time.
Lets Microsoft deploy the software easily without users needing to install it after the fact, but also does not inundate users and orgs with Teams client popups if they are not ready for it yet. Doing this would suffice for portal downloads where app selection is not granular... for managed devices, admins can always simply exclude Teams in their XMLs when deploying via the ODT.
Clouise Fin commented