ignored.packages aren't ignored by packrat::status()

I'm trying to develop a package using devtools and packrat but I don't want devtools to included in the packrat library as it is quite heavy and not totally needed for the development process.

I've added devtools to my ignored.packages, here is my packrat.opts:

auto.snapshot: FALSE
use.cache: FALSE
print.banner.on.startup: auto
vcs.ignore.lib: TRUE
vcs.ignore.src: FALSE
external.packages:
local.repos:
load.external.packages.on.startup: TRUE
ignored.packages:
  devtools
quiet.package.installation: TRUE
snapshot.recommended.packages: FALSE
snapshot.fields:
    Imports
    Depends
    LinkingTo

This does mean that devtools is not included when I use packrat::snapshot() but packrat::status() still reports it as a package not reported in my lockfile:

install.packages('devtools')
## Installing package into ‘/Users/lvines/code/global.modelling/packrat/lib/x86_64-apple-darwin13.4.0/3.3.3’
## (as ‘lib’ is unspecified)
## trying URL 'http://cran.rstudio.com/bin/macosx/mavericks/contrib/3.3/devtools_1.13.3.tgz'
## Content type 'application/x-gzip' length 435816 bytes (425 KB)
## ==================================================
## downloaded 425 KB
## 
## 
## The downloaded binary packages are in
##   /var/folders/6m/ltph82853s31xytwwbt2mfhctkg_t1/T//RtmpflPSZE/downloaded_packages

packrat::status()
## The following packages have been updated in your library, but have not been recorded in packrat:
##                library   packrat
##     devtools    1.13.3        NA
## 
## Use packrat::snapshot() to record these packages in packrat.

packrat::snapshot()
## Snapshot written to '/Users/lvines/code/global.modelling/packrat/packrat.lock'

Reproduce the configuration using packrat.opts with devtools under ignored.packages, then compare packrat::status() with packrat::snapshot(). Trace how ignored.packages is handled by both entry points; done means status no longer reports ignored packages as unrecorded while snapshot behavior remains correct.