You may be right but also remember that in JW life meetings,assemblies, field service etc all are common topics of conversation. Your daughter commenting on a day out at the weekend may be enough for a JW to ask why they weren't at the meeting or on the service.
That being said JWs are nosy about other JWs and have serious issues with personal space and snooping. Just monitor the situation for now and be aware that now the cat is well and truly out of the bag if they weren't snooping before they will be now.