Even in all the excitement, Clare had the presence of mind to realize something was different compared to last time she'd put the dress on. She quickly realized what had changed. She was wearing heels now, and they changed the position of her body.
She was a little concerned, but she repeated the fingertip test, and the dress still passed it. Everything was fine. She even took a picture of herself doing the test, so she'd have evidence if anyone queried it!