I would have contacted the locksmith tech to get additional details before assuming it was tenant damage.

The relatively low price tag and day 1 cash flow prospects are enticing.

It could be possible that he is an honest guy and just using outdated marketing methods which is DAMAGING his brand and reputation. 

If they failed to pay the bill and utilities are shut off, they are responsible for any damages caused.

You can't send a prospective guest your number either (until after they book and pay). 

And that mistake came back to cost me tens of thousands in lost rent and damaged houses.

I live in a lower-income area, so I figure that the better tenants you will get with a safe house, the ongoing safety the tenants feel, and the lowered risk of a break-in (when occupied or vacant getting ready to lease), and reduced headaches/vacancy/potential damage are worth the marginal up-front cost of having it installed.

Your question about hydrostatic pressure is getting into the weeds for sure...I would ask myself, does the potential water infiltration have the possibility to damage the unit and tenant property?  

Finally from a purely from a cash outlay prospective short term, you could rent a house with roommates and your payment would still probably be Lower than house hacking because rates are so high, over the long period 5-10 years obviously it would cheaper ti buy, hope that makes sense 

@Stan MendozaRecommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.Property Class will typically dictate the Class of tenant you get, which greatly IMPACTS rental income stability and property maintenance/damage by tenants.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a property in Class D area to Class A standards, what quality of tenant will you get?