tourist visa rules korea illegal work tourist korea immigration risk immigration overstay decision Korea korea tourism guide tourist overstay Korea consequences taxi at night Korea 서울 쇼핑 환급 VAT refund Korea korea connectivity 한국 세금 환급 late night bus Korea Myeongdong tax kiosk tourist medical emergency Korea overstay exit risk Korea tourist entry denial korea Korea tax refund hospital visit tourist Korea korea mobile internet Tax refund in Korea missed last subway Korea 공항 환급 방법 esim korea visa free korea k-eta korea korea sim card overstay clearance Korea visa violation travel korea travel to korea night transportation Korea korea entry requirements 외국인 택스 리펀 tourist exit record Korea tourist exit procedures Korea korea travel tips