[systemd-devel] How safe are D and R directives for systemd-tmpfiles?

[Amish]

Hello,

I am interested in knowing how safe D and R directives for tmpfiles.d are?

If by some accident OR some packagers malicious intent - someone places 
a file with "R /" in tmpfiles.d, would this erase everything?

Does systemd have a way of specifying that R and D should be applicable 
only for /tmp or /var/{cache,run,tmp} only?

I could not locate anything on man page.

Thanks in advance,

Amish