have always had more than one set of skis in our bag - sometimes have 2 adult and 2 kids ski's and always only ever paid for 1 ski carriage. Worried about the 2 boot bags but so far so good!
Most places dont mind as long as it nots over max limit , they cant force you to open it , unless its a suspicious item, shape or object , then only airport security can ask or stop you to do it