No, a collision is not possible.
The way that app links and universal links work is
- Your web page contains a URL to a file on your web server
- The file contains the information that tells the device what app to open.
The link might look like this:
The file might look like this:
"paths": [ "/wwdc/news/", "/videos/wwdc/2015/*"]
"paths": [ "*" ]
So in order to create an app association using of of these links, you have to own a server that matches the domain in the URL.
You can only put files on web servers that you own, of course; nobody else can (unless you have given them permission or they have hacked you). So whoever owns the web server also owns the app association. No collisions.