Hello,
We are currently using the CNAME wildcard to provide a whitelabel CMS to clients. This works great. However, using a wildcard means that all requests for non-existing domains go to sitejet.
As we have a fair amount of sub-subdomains (like tool.project.ourdomain.com) and projects come and go over time, this means sitejet is probably receiving some data from old projects that a third party did not turn off. Not a big deal probably, but it seems unnessecary.
It would be preferable to CNAME only those DNS records that are required.