1. "reasonable" is going to be different for every person. In this case it seems that the accepted "reasonable" telemetry to be on by default is None.
2. There will always be group of people who will never accept any level of telemetry.
In my opinion, the best approach to telemetry is to ask on first use. Explain clearly what telemetry you are sending and why. If this ever changes on a future update you ask again.
Doesn't work in firewalled / airgapped environments. Don't want to pay performance overhead from errors when it fails or configuration overhead to keep it off. What's considered reasonable can be changed over time and may not be defined by the end user. Potential side channel for data exfiltration if someone figures out how to abuse it, or mask stolen data to look the same. You get the idea.
> Don't want to pay performance overhead from errors when it fails or configuration overhead to keep it off.
I've seen times and times again applications going apeshit when checking for updates (or the standard calling home) on an unstable/firewalled network, they enter endless loops with no back-off delays. They just assume it will work. It's maddening, because my firewall defaults to drop everything.
OnlyOffice is incredibly aggressive if you dare to firewall it, it will do several hundred thousands connection attempts when you start any of its components.
But let's be fair here, even IF google were to implement opt-out telemetry in such a lazy way, it would get fixed soon enough after complaints.