My Subaru dealership didn't want to do any warranty work for me - they'd try to suggest that I'd be charged if there turned out to be no problem with the car (I took it in for the package shelf TSB, and also for the passenger heated seat, which was far slower to heat up than the driver side).
Ultimately, because my car was a lease and I didn't want to have to deal with the hassle, I just left things as-is.
Second time I had to deal with the service department, I had just knackered my wheel bearing (put a wheel off the tarmac on my first track day).
I described the problem to them, noting that it was my driver-side front wheel that had the issue (resulted in a humming sound and very slight vibration in right hand turns).
I told the tech that I had done it myself during a track session - to his credit, he offered to fix it for me under warranty anyways because I was upfront about it.
When I got the car back, the vibration was still there, so I checked the confirmation sheet: it said they had replaced my passenger side wheel hub

.
When I told them about it, they said there was nothing wrong with the hub (well, duh!), and that they didn't hear any humming from the front wheel (guess how I realized that they didn't fix the correct wheel hub).
I got so fed up with them, I just opted to buy a used wheel hub assembly on eBay (whoever wrecked their FRS, thank you), and did it myself. Problem solved.
I've also mentioned on here before, but in another incident with another Subaru dealership (from London ONT), they billed me $55 for 5 minutes of work that I did not give permission for, unrelated to the issue I brought the car in for (I brought it in, suspecting a faulty battery, and they went and fiddled with my Injen intake). It took a few emails and phone calls, including threats to report them to Consumer Protection Ontario (they had broken the stated rules requiring 1) explicit permission from the customer to perform any work; and 2) clear disclosure of fees/costs before work is done), but I did get my money back (more of a principle thing - I didn't feel like letting them get away with underhanded business tactics).
In short, Subaru service departments have given me plenty of justification to bring my car to independent shops or to DIY henceforth.