Backlink Outsourcing & Verification

For those of you who outsource your backlinks; how do you verify the actions? I am assuming a list of all links created is sent from the contractor(s).

Do you manually check each link?

Use an automated process? If so what?

I am strongly considering outsourcing but only if there is a realistic way to proof the work.

If they're blogs you can use scrapebox, and xrumer can check profile links I'm pretty sure

If the list is short just check them manually. If any links at all aren't there, bring it up. This lets them know you're checking behind them.

Hopefully you'll eventually have some trust and will only need to spot check.