I haven't played BL in ages, never used Glass either, but my key was compromised. I did link it to Steam when it first launched on there, but I think it may be related to the CBMHosting leak that happened a few years ago. That was the only other time my key got compromised (nothing happened) til now.
Honestly, if it's possible to deactivate just the key and keep the steam account linked, that would be cool. I understand if you can't.