On 1, how honest is the "it will interfere with emergency services" reason? I've heard police in particular have unofficially switched to cell phones for sensitive information.
It is honest. Public safety is all up in VHF,UHF, and the 700/800mhz bands. Other then going to digital voice (P25 mostly) there hasn't been much change in the tech. Its just radio.
Cops may use cellphones for sensitive stuff but dispatch and calls for help still use radio. Ambulances still use normal radios and "MED" channels in the clear to talk to doctors on the way to hospitals. FD's use normal low power portables while on site working a fire. If they get stuck that is how they call for help.
If a boater needs help he is still going to call the coastguard on VHF.
There are digital trunking systems that hop around on a SET number of channels but they can still be interfered with if something is operating on their band like anything else.
There are bands like FRS,GMRS,CB,etc that you can mess around on and no one will care. The 27mhz CB band is a total free for all with guys running messy 2KW stations. Since they are contained down there the FCC doesn't care. This would be the best place to play around in IMO.. right in the middle of all the other chaos.
No good will come of messing around on public safety bands. It will get you noticed very quickly and may actually interfere with an emergency call.
You can look up what your area uses on sites like http://www.radioreference.com/...
Its all public info and licensed by the FCC.