I once tried to get one for almost a whole day and never got one so i gave up. then the next day during my routine i got one randomly without even meaning to. Oh the beauty of Not-Even-Trying.
- - - Post Merge - - -
The whole day. And that was when I realized that the pwp diving trick seems to have been patched.
I highly doubt it was. It still works for me.
The thing about the diving trick is that you are far away from all your villagers. Being far away for long enough (about over 5 minutes) will cause the all the villagers far away enough to be able to have an event (the ping) triggered.
Depending on where you are when you dive, there might be a chance that a villager is still close enough to not be affected, but you don't need all the villagers to be far away enough, just the one you want to ping you.
I've gotten a ton of requests accidentally through just setting down my game while distracted by something, walk to the other end of town and had a villager ping me. You don't really need to be diving, just be far away enough for long enough :0