Jingles has done absolutely amazing job with his service.  Linkshorters are Inherently unsafe. 

 Example shorten link:
https://w3.do/jingles-dev/ndk
Link preview (like doing a curl and get page meta): 

 That will solve a lot of problems. 

 W3.do short links are 301 redirect. 
No surprises to redirect you to site you don’t expect, as even those “links previews” can show up the actual site’s meta data. 
Like all links on internet, it’s user responsibility to keep themselves safe. 

 I concur, the user bears the ultimate responsibility. By the way it's not something specific to your service. I really think you have done a great job. If used with responsibility it can be a great tool. 

 Yup