You know what, normally I'd wholly agree with you protecting your own (home) time.
But in these circumstances, we all have to pull together in the same direction, and for some of us; that means working strange hours (I'm home with DH who also works full time, and DD3).
I don't want to work these odd hours, no one on my team wants to work these hours, but just right now - we're doing everything we can to support each other.
I don't mean being fully logged-in, but keeping a vague eye on emails, knowing that I have colleagues who simply CAN'T work a normal business day at the moment, and me not being around to support them makes their day even harder.
I'm in a senior leadership position, I have 9 team members, each of whom manages a further 8-12 people. It's important that:
a) I'm visible
b) I'm helpful, that no one is blocked by me not being available to carry out my part of the task