You believe wrong. Also, even if they are, traveling with an instrument, especially and old finicky one (and they do get finicky when they get old) can throw it

You believe wrong. Also, even if they are, traveling with an instrument, especially and old finicky one (and they do get finicky when they get old) can throw it out of adjustment, a seam can pop open, a string can go false, etc. The new ones, on the other hand, since they were actually new, were probably being maintained by their makers, who undoubtedly made sure they were in top condition when they went into competition with a strad.