If they've come into contact with similar flowers, they'll recognize that it belongs to the flowers themselves. Closer examination reveals that one of the flowers is slightly squished, as if the flowers were removed and then put back into the vase.

They may remove the flowers to look inside the vase. The vase itself is opaque.

The vanity does have some drawers or compartments to look in, but these have already been explored by previous visitors so there won't be anything of note here.