Is it a good practive to warn the users before switching from mobile to desktop website?

We're developing a mobile site for an existing large desktop site. The first implementation is a "Mobile MVP", so not all pages are implemented on the mobile site, and sometimes we are just forced to redirect the user to the relevant desktop page.

My question is, should we warn the user before leaving the mobile website as a result of e.g. clicking a link to some page that is not mobile-optimized? Or should we just continue as normal?