If you don't see ANY signs out, its a good sign that your city is actively picking them up and enforcing the code. 

I would build a list of distress property owners Code violations city liens vacant property registration and such.

Are you saying I approach the appropriate town office as if I were a contractor hired to remedy any code violations the property may have?

City code enforcement had already started gunning  for these properties and now all I can afford to do cut the grass and clean up the exterior.

It's a lockbox so one would need to know the code to open it to get the key.

If you haven't gone into escrow on a property or found one that your interested in at this time then just send in writing to cancel the buyer agreement or ask to have it altered that the agent only be paid on properties that they give you info on.

Specifically: Property condition - properties in poor physical condition, that have code violations, or structural/pest issues are viewed poorly by lenders.

VPM requires the tenants to front the costs to rehabilitate the property, pay all the overdue taxes, and resolve any outstanding building code violations associated with the property, Wisconsin’s complaint states.And, if the tenant does not remedy those issues within a short period of time, VPM evicts the tenant and “repeats the cycle by renting the uninhabitable property to yet another Wisconsin consumer,” the Wisconsin DOJ said in a statement.According to the complaint, VPM rented properties with sewage in the basement; black mold; lack of water, heat, or electricity; insect infestation; and multiple code violations; among other issues."

There may be codes liens. 

Purchase price: $120 Sale price: $850,000 These were three properties owned by similar family members who all had unresolved estates, unpaid property taxes, code compliance liens piling up, and family members who were not amicable with each other.