Keep in mind the first people you need to satisfy are not in FRA, they are the airline at her point of origin. If they think she could be refused entry, they might decline to fly her.
Next do check that nothing about the visa allows entry and exit days to be in immediatly before after the valid days. [I've not heard such discussed in ages, but can recall hearing that concept some times in the past - not sure which country it was in relation to.]