Are clear bags required at every Seoul show?

No. Some tours ask for them; others do not. Follow that show’s notice.

Can I bring a power bank?

Often yes within a Wh limit printed on the notice. Oversized packs are turned away at security.

Ingressos · K-pop 콘서트 가방·입장 규칙 (서울 공연장)

K-pop concert bag & entry rules (Seoul venues)

Arrive early enough for bag check — floors move slowly when sticks need pairing.
Carry the ID that matches the ticket name.
Venue maps and exits: Seoul concert venues.