The Bikefinder tracker is equipped with a movement sensor. The sensor always sends positions while the bike is moving.
This means that if the bike is still, you will not get any new position. This is to save battery so you don't have to charge the tracker so often.
Don't worry though, if someone is moving your bike, you will get a notification in the app, or a new position (see modes explained section for more info on this)
This movement sensor is measuring all movements on the bike. Just remember, if the bike is put in a place with strong winds, or in a bike rack where people are putting their bikes, you might get some false alarms due to these movements.