Now thinking of the other "caveats", I am more thinking along #2 and a pin switch.
I would assume that the bulk of the "noise" is coming from the door speaker, but how loud is the noise coming from the tweeter alone? I could likely deal with just the tweeter.
After modifying my sound system I think I can say that 100% of the sound is coming from the door speaker. I installed a mini-switch on the wire identified earlier in this thread and it really helps reduce the chiming. You can cut that wire and live without it, but you'll have to be attentive to leaving headlights on, etc. I installed the switch adjacent to the fuel door switch and it looks good and gives me the chance to exit my car while it is "running" without the chime. If you've added an amp that chime can really get loud, so reducing it is very helpful.
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