I was banned about a week ago because I had a shotgun, the admin thought I was weapon hacking and banned me without warning or giving me a chance to explain how I got it.
I picked the shotgun up from a police ranger whilst in buildmode making a race. Want proof? Try playing the race ShotgunRanger made by me. At the starting grid is the secret shotgun pickup that Andre coded into the game and the car which you race in is a Police Ranger (which gives you a shotgun upon exiting the vehicle - this is hardcoded into GTA)
That is how I got the shotgun.
I commonly play with Thrasher and FireFox and they both know I don't hack.
My IP is in the bottom right hand corner of this post.