Using the subversion switch command to keep up with quarterly branches

[Mel Pilgrim]

I track the quarterly ports branches so that I can build ports from the 
same tree as binary packages so that I don't, for example, have to build 
all 2783 packages on my dev VM, just the 13 where I need non-default 
options.  Yes I know, "That is not the intended use, ma'am," blah blah 
void my warranty, etc.  This is a dev/preprod instance, I am TRYING to 
break it.

Since the current quarter's branch name changes each quarter (2016Q1, 
2016Q2), you can't just relocate and update, you need to use the switch 
command.  I really just want to keep up with the current quarter and 
would like to take advantage of already having most of the branch 
already downloaded.

Is it safe to use the switch command to jump ports quarterly branches 
(assuming a read-only check-out), or are there special gotchas in how 
FreeBSD is doing the branches?