Kaito: NEVER. Like, he cried once in his entire life, and that was when his dad died.

Keiichi: On the other side of the coin, this one cries all the time >:

Yoko: In private, when she loses a friend or something along those lines.

Trucy: Also in private or with Daddy!Nick, sometimes over the way her life has turned out, but usually she just looks really sad and never cries.

Mitsuru: Mitsuru is also a private crier, usually when something very sad happens like she loses a family member or something.