Mostly never. People are using too many apps today and they don't have time to read every TOS. I'm not talking just about gambling. I use more than 20 apps on my phone. And betting sites have mostly similar TOs so I just assume everything will be fine and just click accept.
Same thing also happened to me that I didn't read the TOS of a gambling site. This is my honest answer. You used almost 20 apps but I use more than 40 apps++ regularly. The maximum is browser and gaming apps. I have almost 5 betting apps on my phone and I found almost the same rules everywhere.