for any crime, including up to murder.

Sounds unconstitutional.

Even child molesters are allowed to stay in a town as long as they are so many feet from schools, etc.

Anyone else ever hear of this?

Sounds pretty unenforceable, in any case.

(still not a lawyer)

Unless they are going to put an ankle bracelet on them, I don't think it would be possible to banish someone from a major city.

Sounds like something the city passed to make them feel like they did something, but it really has no effect on the perceived problem.

Slate agrees with the general consensus here:  it's not enforceable.

If the court orders you to stay away from an area and you do not you have another issue besides the second arrest for prostitution.  It in effect might be used like a restraining order.

Not a lawyer, but thinking through how it might play out.

They have been imposing similar ordinances in Calif & Vegas for years.

At least as to being told to stay away from certain areas, never heard of an entire city ban.  No problem with the constitutionality, "if you don't want to have it be a term of your probation, how much time do you want to serve in custody instead?"  They are particularly diligent about it in Vegas and some of the casinos, being all on it with face-recognition technology.  As noted above, it can be difficult to enforce but with the spread of computers and increased connectivity, it will get easier and easier.  So always remember the key: it's no illegal if you don't get caught!