Surface twitter account is saying otherwise.
Well, the PR person behind that account is wrong. Every time you create a new user, it installs the default applications. Mail, Calendar, Bing, News, Finance, etc. Each new user is initially given the RTM versions of those applications until they go to the Store to update them. In order to have those RTM builds of those apps, the original version of each never gets deleted.
If you want to check for yourself,
Get access to the %ProgramFiles%\WindowsApps folder and view apps source code | Caio Proiete (EN)
However, if you mess up your permissions (like I personally did, because I didn't follow this guide, and I didn't back up my permissions) you can end up with Metro apps failing to load until they are uninstalled and reinstalled, so you'd have to be careful.
That being said, I only see storage usages of around 100MB per app for the Travel and News apps.