Here's a helpful chart: https://whitecathearing.com/when-is-sound-dangerous https://whitecathearing.com/when-is-sound-dangerous At 100dB, a safe dose is about

Here's a helpful chart: https://whitecathearing.com/when-is-sound-dangerous https://whitecathearing.com/when-is-sound-dangerous At 100dB, a safe dose is about 15 minutes. Blowing horns all day for weeks on end poses a significant risk of severe hearing loss. Per affected person, a hearing loss payout can be up to around $100k. Given the ~1M people in Ottawa, I would expect the physical damage to persons in the area to exceed the millions of dollars in your "[usual] large-scale protest."