Inspections will obviously reveal the truth.

No need to call the employer; they are unlikely to reveal such information.Also, remind the tenant that in the event he changes his contact information, he needs to notify you right away.

I've funded loans on properties with damaged siding as well it just depends on what the appraiser mentions on that appraisal report or if the underwriter somehow gets a hold of your inspection report through unscrupulous means and its revealed there are issues with the siding.

Inspections revealed that two of the properties needed a new roof, and one would need sewer work at a cost of between $10 – $20k. 

This goes hand in hand with finding your ultimate buyer - if you shop the deal around and find that your buyers don't like it at that price, that's when you go back and say "our inspection revealed more issues than we were aware of", etc.Last - you don't give the seller the earnest money.  

Either way I just got the inspection which revealed a plumbing issue that I wasn't aware of.

This building is being listed as "Recently renovated", a City of Chicago building permit reveals a permit for interior renovation in late 2012. 

Plumber C for the damage that ensued, the homeowner for not revealing the red tag that would have caused you to fix it....).  

Second question, Inspection revealed knob and tube wiring on second floor unit.

It will often reveal important information about the seller and the deal.