Depends on how good your lawyers are when negotiating the service contract. If you have it set up so you counterbill for downtime, and your definitions for "downtime" are granular enough, you can make money on the service contract.
Happened to one of the ASPs I subcontracted for; the end-client tried to counterbill us for more than the service call claiming I was late to site, when I provided exemplary less-than-1-hour response time. The only thing that saved us was the fact I anally SMS-documented every step in their obscenely convoluted security process, with arrival time in front of the rack to the minute and every ridiculous step their bridge associate made me take in troubleshooting before admitting the fault was in fact infrastructure rather than the hardware we were responsible for.
When the WO for said infrastructure work came across the wire the next day, I noted the address and politely declined citing
allergies.
Guess my techy-sense was tingling on that one; it wasn't until almost 2 weeks later the counterbilling nonsense went down.
mnem
*currently trying to un-fuckerize a Android TV box with UI defaulted to Chinese*