I can't speak for all areas but IMHO in my area it is relatively easy to tell a BB from an Adult Doe, and experience has taught me this over the years.

No different than any other time you plan on shooting at something. A Bowhunter should always positively identify their target before loosing an arrow.

If you are Ok with killing a BB then shoot away. I won't because if I'm after a Trophy the choice is obvious, and if I'm after meat then there are much better choices available that will provide more meat. I am lucky that I don't have to feel desperate or feel I won't be able to kill a Deer if I pass a few up.

I know due to some areas and some hunters lack of time to spend in the stand their choice might be different, and that's Ok.

Dan