I have an old auto snail type horn that I may end up installing in the similar location....it's better than nothing fer sure. The ability to get the attention of riding buddies is a good thing. Whether it's because their cooler lid isn't fastened and the contents are spilling out onto the trail, or warning them of road traffic coming up behind, etc, etc. Yelling and waving doesn't cut it.
I just think louder is better as these machines are pretty noisy.

I'm also thinking about turn signals for this winter....there is a bit of road running around my place on well travelled asphalt and once the full doors go on, hand signals become almost impossible/effective.