Good point.It is possible your newly acquired Blackbird would always feel a bit tainted.
On the other hand: if you purchase it after your GRUME, it might shine a lot more, since you would associate it with your perseverance.
I was supposed to be on a GRUME break this holiday season but spent my designated shaving funds on some soaps and that is the matter of content.
If those soaps weren't purchased then the Blackbird would be the reward for good behavior, now it'll be like Cheating.
Well, this clears it - no Blackbird for me since I already spent the designated funds earlier on something else.
This will be a good lesson for future - not to burn out future prospects in favor of short term comforts.