What happens when you click on a failed short URL? You can’t go anywhere. You are stuck on an island. You can’t browse the main index page since the domain you are given is the domain of the URL shortener service. One way of finding the true URL is to check if the URL short service has a lookup function.
If it doesn’t, you’re pretty much dead on the water. That’s dilemma for short URLs. It works great when it does, but if it doesn’t, it’s useless. One more thing, clicking on a shortened URL sometimes requires a leap of faith since you don’t know what page you’ll be landing. This is especially troublesome for pages that contain malware and viruses.
If you are giving out short URLs, it always good practice to check if the short URL works. If you don’t trust other services, you can always start your own.