The 'notify me when my bike detects motion' notification is a sensitive alert function that you switch on when you park your bike in a place where you want to be alerted with every movement of your bike. With a detected movement you will receive the message 'motion detected'.
You will also receive this message when someone for example bumps into you bike or puts it aside without any ulterior motives. Only enable this notification if you want to be alerted immediately with every movement.This may be the case, for example, in places with an increased chance of unauthorized use of your bike.
Do you want to use the standard security notification? Then use the 'notify me when my bike has started moving notification'. You will receive a notification when your bike detects a sustained movement, for example if someone ties to steal your bike. This notification is already on by default.