Bullet Shielding

Short answer: yes, but you'd have to do it on purpose to make a bot-sized shadow.
Bullets are just a short line segment, so you can optimize for maximum shadow size with that in mind. If the bullet is very close to an opponent when they fire, the shadow that is will cast will generally be larger. The more distance between the bullet's intersection with the enemy's wave and you, the larger the shadow grows. Also, if the bullet is perpendicular (not pointing directly at them) the shadow will be larger because it has more surface area relative to the wave. If you watch a bot that tracks bullet shadows long enough with debug graphics turned on, you'll start to notice all that.