I used to know a 20-odd year old blind paso... he could and would get in or out of any field he wanted and any time. Fences, gates, ect did not matter. There is every possibility that she broke out somewhere and got in with them. To ease your mind about her being caught by one of the studs, you can get her scanned at 21 days and make sure nothing is there.
Stop for a minute, open your mind, learn. You may not agree with what I say, I may not agree with what you say but we will both learn something new.