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