Having received a significant sum of money (not lottery) I can tell you that there definitely are some people who either presume that you will pick up the tab..
But how did they know you’d come into money? My DC got an inheritance as teenagers. We impressed onto them the need to keep quiet about it, money is no one else’s business. Only one local friend of mine knows, and that is because her DC had also inherited substantially and I wanted advice on how they handled it. As far as I can tell, none of our DCs friends know they have a nest egg tucked away.
We have also had an inheritance, which friends could guess at as I lost my 2nd parent, but they wouldn’t know how much, nor about the other windfalls that came around the same time. We spent some on a US holiday, but no one knew we paid for an upgrade on the flight, other than the 4 of us!
I occasionally do the lottery, not very often but if I won, I’d keep quiet. Finish work, put some in trust for DC and other young family, maybe buy a bigger but not OTT house, then use the rest to travel. As a pp said, no one knows exactly where you stay, or that you have the top suite on a cruise etc. We would just say that we were enjoying an early retirement.
It’s not hard to keep quiet...