the "you ok?" text from across the room... is this a us thing or universal?

club night in london last weekend and i caught myself doing the thing again where i text her from like 10 feet away just to check in. she was chatting w a guy and i didnt wanna interrupt but wanted her to know i was watching out and asking if she's good. she replied w a thumbs up and a winky face within seconds. felt so normal to us but my mate was like... you guys text each other from the same room?? yeah we do. is this weird or do other couples do this too? texting feels less invasive than walking over...