LostSoul
Adventurer
Flavor inspired by the rules lets you show, not tell - the players may notice these customs, wonder about them, forget about them, and then later, when they have these kind of spells, have a flash of surprise when they realize the underlying pattern. And it will actually be the players realizing it - not just you telling them "you realize that those coins must have been to prevent scrying".
That's cool.
It's hard work to look at all the spells and come up with flavour like that. It's also only going to work once. And if you want to change your setting, the players will wonder why there aren't beads everywhere or secret touch handshakes. In other words, the rules define your setting.
Which is cool if that's what you want.