I suppose it really depends on your threat model. I think most offices will be fine with the warning. However, you could configure each device to only respond to the trusted IP address of a HTTPS proxy which at least lowers the attack surface for snooping.
wait, wait, wait, are you saying a "trusted ip address" out on the web? or requiring every office to set up their own https proxy? Cause a "trusted IP address" out on the web would just be insane... "Oh, let's just send my login to and give full access to my network to this third party/manufacturer."
