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:
https://<domain>/apple-app-site-association
The file might look like this:
"applinks": {
"apps": [],
"details": [
{
"appID": "9JA89QQLNQ.com.apple.wwdc",
"paths": [ "/wwdc/news/", "/videos/wwdc/2015/*"]
},
{
"appID": "ABCD1234.com.apple.wwdc",
"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.