Yuugo

Q:What happens to cards placed face up in the security stack by effects?

A:They become face-up security cards that remain revealed. Other than rules that specify face-up security cards, the rules apply in the same manner as standard security cards.

Q:What happens upon a security check for a security card that is placed face-up?

A:The check is performed with the card left revealed. Other than rules for cards left revealed, the rules apply in the same manner as standard security checks.

Q:Does a card's [Security] effect trigger upon a security check with that card placed face-up?

A:Yes, it triggers.

Q:What happens if I shuffle a security stack that includes security cards placed face-up?

A:Any face-up cards are placed face down, then you shuffle the cards. After shuffling, all cards are left face-down.