Because the client just wants to have fun? No.
If I ask you? Yes, maybe.
If I texted you ‘hey let’s go to Barleys for breakfast’ out of the blue, I wouldn’t expect you to pay more than the food.
If you text me I’d like to take you for breakfast Sunday
Then I would expect you to pay me.
1 is me volunteering, 2 is you requesting my time. Replace the activity with anything you’d like, still the same but also that’s mostly why I never text people that I want to go somewhere
3rd option if I really like you, you request my time and I give you a huge discount