Although it's not recommended, if you find one with all of the right options it could work. A scanner will be safer and may even cost less once you add the programming costs to the radio cost. Two major cautions though.
First, one minor slip up when you program the radio and you could cause interference to the system (that they will not like at all) and you could easily have them brick your radio.
Second, programming a trunked system into this kind of radio requires a "system key" file, which only the system owner is given. They will only give a copy of this file to shops that they authorize to program their radios onto that system and they will only use it on radios that they have authorization to program on the system. It's possible that they may charge others with a serious crime if they have an unauthorized copy of this file or use it outside of the bounds of their authorization.
See this sticky for some details on what you're asking about.
http://forums.radioreference.com/mo...ou-want-monitor-trunked-system-moto-read.html