Just got back from a simply lovely wedding: an older couple in their thirties, very faith-filled. Some non-Catholics attending.
The leader of the prayers of the faithful was a young lady, perhaps ten-ish. I noticed at the rehearsal last night that she made a straight-up arm gesture for the assembly’s cue to respond. I considered suggesting she not do that, but I felt a spiritual nudge to leave it alone.
The guests sang as well as most any mixed Christian assembly at a wedding. The spoken responses were rather limp. I think the girl’s gesture helped after each petition, however. Despite that, I’m still hardly a fan of it. One or two of our students use the gesture at daily Mass. That annoys me. In a much smaller worship space, I don’t see the point of that at all.
Sit in the purple chair, if you will, and render judgment. Are flapping arms ever helpful? Or should the reader communicate better with body language and voice inflection when to respond?
Catholic Sensibility 
It’s more justifiable:
1. In large spaces where the spoken word is acoustically compromised (sound systems make make it louder but not better)
2. In ritual Masses (funerals, weddings, sometimes baptisms) where there is a higher likelihood of attendees unfamiliar with the rite.
Eh, not a fan. I’m not going to let it ruin my day, though. (Now drum sets at Mass…)