Sharing your current location with someone is a great way to passive-aggressively explain that you’re on your way when they ask where you are. But it also has other uses, and WhatsApp has now joined rivals Facebook Messenger and iMessage in offering the feature (with its own somewhat unique twist). The new feature will be available on both Android and iPhone soon, and it’s accessed the same way...
Visit http://infodrifts.com/whatsapp-launches-live-location-sharing-feature/ for more

I am wondering if somebody will be able to activate live location remotely and track your device without your knowledge.

Anyway, this is a sleek feature, given that WhatsApp uses less data than other messaging apps. A great feature if two friends are trying to locate each other