That question was posed in another thread-and I thought it was a valid question worthy of a more public answer than just in the (different topic) thread it was in.
To answer the question. I turn off my phone, as does he.
I live with Maca and GG. If I am sharing PERSONAL time with Maca, I shut off my cell. If his texts/calls are interruptive, I ask him to shut his off as well.
GG and I rarely shut ours off, but we also don't answer them unless they are the kids or Maca. The timing of our time together isn't prone to interruptions either, so we usually have no problem.
I think it's important to consider your "date time" as DATE TIME. If you were going out on a DATE for the first time-wouldn't you be focused on YOUR DATE and not your PHONE?
On the other hand, if we're just hanging out at home, or getting groceries, paying bills, running errands whatever, that's not a date and it's ok to "interrupt".