The neighborhood had very high and violent crime.

And I really did not want him as he is a registered violent sex offender against children, a renter whose background does not meet my standards. 

In most states you only have to disclose a violent death like a murder or suicide or death resulting from a defect in the property.

The chart shows that 21229 is well above average in violent crime and property crime. 

I would consider York PA a warzone, literally it is one of the most violent and crime ridden towns in the country.The returns look great on paper, but in reality these are tenants with extraordinarily high turnover.

I've seen  reference to prior fire damage, violent crime, warnings about lead paint, etc.If it helps you sleep at night or you feel some type of personal obligation you can warn them.I would just wash off the eggs.

It's like they want the streets to become poor and violent. 

So, with this example, some are not accepting of any prior felonies, some will accept for one non-violent felony, etc.  

Do they only check for violent/sexual crime and threats to other tenant, or is a marijuana felony usually enough to keep a tenant from renting a place to live?

The town have numbers between 6 violent crime and 4 property crime, the average in the US is 3, so its a little higher risk, but I become for $229k a 9 unit full rented.