Funny, but I’m saying it seriously as a countermeasure to the bloat epidemic. An SMS parking app doesn’t even need Internet and works fine. Use the simplest technology to achieve a goal and enhance.
An SMS parking app works fine as long as you limit it to the very specific use case. As soon as the "enhance"-part enters the picture, chances are simplicity leaves the scene at the same moment. Complexity can only be avoided by keeping the problem simple.
It’s easy to find a way to get internet anywhere, but getting an sms message at a phone number is way harder (or easy but expensive); bonus points if you restrict it to local phone numbers only. Lots of countries require ID checks to get a local number and the system breaks with foreign IDs.