Invasive? only as invasive as you let it be. Although, once they've got your plot points, I don't think you can take them away from them. So, don't do the crime if you can't do the time. Or leave your cellphone with someone else while you are commiting the crime.
Since I'm the "they" in the above statement I will say this... I haven't added functionality to SpotWalla for users to delete location data for two reasons. First, no matter how many warnings and confirmations I put int the process, there will always be a "whoops" factor. Second, I'm too damn nice and will probably restore messages as long as they were around long enough to have made it into a nightly backup.
So if someone's certain they want to delete locations or even their account, it's as simple as sending a request to support at spotwalla dot com from the email address used to create the account. After confirmation, I'll make it so.
Regarding invasiveness... I completely agree with the statement that it's only as invasive as we let it be. Each user is in complete control of their degree of exposure. It's entirely possible to fly under the public radar while still sharing your location data with family and close friends.
And even if you want to share a trip publicly, it doesn't mean you do so naked. Secure zones are a way to define reqions of the map where SpotWalla will not display location data. Setting a secure zone around your home, work, grandma's house, etc allows you to share trips publicly while still maintaining some privacy when traveling within a secure zone.
Additionally, you can control the message types that are displayed on a trip. For instance, I use OK messages to mark where I'm spending the night. The private trip I create and share with family and close friends is configured to show OK locations because I want them to know where I'm bedded down. But if I share the trip publicly, I create a separate, public trip that's configured to not display OK messages.
Anyway, the point is that if you want to fly under the radar and still provide family and friends with your location data, it's possible. Now there are some that will argue that once your location data hits the net even if it's encrypted, it's out there for prying eyes with the right technology. To a small extent, I agree. But the technology required to do this is extraordinary.