If you walk up to random people in a cafe, park, or embankment (really?) and ask for their numbers, you could get a positive response, but it's equally likely that a women (or even a group) will start yelling at you for doing so.
That's what I'm saying about nowhere to ask safely. Some women will be totally fine with being approached, and others will not, but there is ZERO way to indicate to others that information.
We need to bring back the whole gay handkerchief system and adapt it to the whole population, If everyone wore an accessory or object that indicates your willingness(or not) to be approached it would make the whole situation 100% better. Like a stoplight party, but all the time and with slightly less impact on your whole wardrobe.
It is a regular occurrence. Regular enough that it's been reflected in popular media for decades. They even make entire movies about "boy gets rejected by popular girl, boy transforms himself to win her over, boy decides he doesn't need her anymore because she's mean"
Are you honestly so naive that you think those initial rejections don't happen in real life? Everyone saw them at high school, and everyone saw them even more on social media when said girl spreads it around to cyberbully the boy even more. It's been more than 20 years since I was at high school, and even when we didn't have cellphones that shit still happened, and it didn't stop at University either.