Player would be banned for that?
Customization UI/HUD allowed?
Hello there.
Nope!
At the current point of time, customizing your HUD as well as using a Mumble overlay is fully allowed. 
I’ve even made a Steam guide on how to customize the HUD.
I can’t access Steam right now but you should be able to find it.
You can customize your HUD. Google Dirty bomb HUD configurator. It’s really straight forward.
You can also change where all of your UI elements are by editing “Documents\My Games\UnrealEngine3\ShooterGame\Config\ShooterUI.ini”. As always, remember to backup your “ShooterUI.ini” file.
The settings I use are:
WeaponAmmoPosition=(Align=(V=HA_BOTTOM), Attach=(H=HA_RIGHT, V=HA_BOTTOM, VA=“PlayerHealth”), PixelOffset=(X=510,Y=-120), Skew=0, ShadowOffset=(X=-1, Y=-1))
AbilityCooldownPosition=(Align=(H=HA_CENTER, V=HA_BOTTOM ), Attach=(H=HA_CENTER, V=HA_BOTTOM), PixelOffset=(Y=-40, X=-55), Skew=0, ShadowOffset=(X=-1, Y=-1))
PlayerHealthPosition=(Align=(V=HA_BOTTOM), Attach=(H=HA_RIGHT, V=HA_BOTTOM), PixelOffset=(X=530, Y=80), Skew=0, ShadowOffset=(X=-1, Y=-1))
MinimapPosition=(Align=(H=HA_CENTER,V=HA_BOTTOM),Attach=(H=HA_CENTER, V=HA_BOTTOM),PixelOffset=(X=-200, y=-30), Skew=0)
Only edit the specified lines, don’t delete the entire thing to just put these 4 lines in.
You can also create your own at http://wezelkrozum.com/temp/xt_hudconfig/v3/ but it seems to be outdated, I haven’t gotten any accurate results from it.
Make sure to set your modified config file to “Read Only” before launching DB else it will change it back to default.