I flew SJC - IAD the other day and saw the Frontier operation handling the DH flight. They were dealing with an inbound passenger that was filing a missing bag claim and the counter agent mentioned that on a daily basis there were always bags missing. I mentioned to the passenger to file a Happy Bags claim. First note -- SJC needs better signage for Frontier and Independence because their front counters are hidden. I had to ask Jetblue if they were handling the contract service for DH because I couldn't find the counter, and I've been through plenty of airports where I can't speak the language of the locals yet found my appropriate counter. I didn't have any problem with the Frontier staff, but my situation was also regular operations. The TSA staff were excessively slow but it was fortunate that there were very few people waiting.
With only one flight a day, I can see how SJC has contract crew. With three A319s a day (~400 passengers) I'm surprised there aren't DH employees (at least a few) at SFO. Many of the RJ outstations have less seats per day than that and have full DH staff.