I have an employee at a mid-size IT startup, which is texting during our Daily Standup meetings. It's just a text or two at a time, but it's very emotionally involving for them, with obvious facial expressions, and has been going on for 3 weeks without a miss.

I'm fine with people doing personal things at work, but want to avoid this during the 10-minute window when we're supposed to engage each other as a team. 

It's easy to ban phones in just this meeting. But long-term, I want the delineation to be work use vs non-work use, rather than meeting duration. To keep phones and laptops fine for meeting-relevant work, but not for personal conversations, at least not the romantic kind. 

**What would be the least intrusive way to ask an employee to avoid personal texting during meetings?**

The options I've considered include:
 - Discussing group norms without singling anyone out. My concern is that it would be obvious who it's about. 
 - Mentioning this "casually". I'm worried that it might feel like I'm intruding into their personal life. I don't know if they know that I know about their office romance, and would rather leave it private. 
 - Asking them not to use the phone during meetings at all. My concern is that this feels rigid and might increase our power distance. It would also be singling them out. 

I don't want to restrict cell phones as tools, only their use for entertainment, and only when it's important to be engaged in the work. We do check them in meetings for work reasons, like looking up the calendar.

I'm not the employee's line manager, which I'm still hiring, and don't work with them much. Still, as the ranking company officer that's actually in the office, it falls to me.