Plus I find a little throttle pop to be less annoying than a horn, just as effective in some situations and less likely to provoke an ass hole to drive up alongside me so he can flip me off and scream " I see you."
has that really happened? If so you can take solice in the fact that that person has way more issues in his life that don't relate to you.
I have had all manner of things yelled at me while riding. I don't take it personally, I rarely hear what they are as I float past and I just assume they would rather be where I am than I would be where they are. The best one though when when I used to lane split in the city, I used to get "you're cheating" often. Always made me smile.
But back to your muffler as a warning system - the science doesn't support it. The majority of a motorcycles sounds are behind the bike because that is where the mufffler opening is. Unless you are ungodly harlye loud most new cars aren't going to hear you even if you are right on top of them. You can't hear any bike from the side or behind (except my ducati and my ironhead more on that in a minute) from inside my wife's audi - not the kerker race baffle cb750s, not the kerker race baffle equipped gs750, not any friends bikes with micron cans or supertrapps.
engine noise is not a deterrent to anything, full stop. Even in situations where they can hear you it poses as much as danger as it does help you (triggering road rage, startling drivers). Loud pipes do not offer any more safety in this hobby - proper training and gear does.
The point of this conversation is if you are going to own a loud bike, own up to it and it's consequences. I do. I own two bikes with open pipes the ironhead HD and a ducati sport 1000. I do not pretend them being loud offers me any safety, and I get called arsehole by other motorcyclists and I own it, I am an arsehole. The ducati I had set up as a track bike but then came to my senses and realized I wasn't going to actually track it so it is tuned and set up for a set of "for race use only" open megaphones. to make it quieter I would have to retune the bike and spend money on it. The HD came with the open pipes and I have hated them since day 1. In fact I just put baffles in the pipes because it is uselessly loud. I may actually put a factory XLCH highpipe and muffler on it because it needs to calm down.
I am a big fan of informed decision making. I have supplied you to the best of my knoweldge as much that surronds this decision. The rest of the decision is up to you. I would feel remiss if I didn't mention that loud pipes do not save anything and it might turn you into a social outcast amoung a group that is already some what of a social outcast. The fact that you want to argue your point that there is a situation where a loud pipe might actually save something indicates you need all the information you can get because it just isn't true. the science doesn't support it, the stats don't support it, it's a myth. let it go.