Yes, I know of one repeater in my area using DCS on 2m. The story I heard is that this repeater used to use CTCSS, until they had a problem with someone behaving badly, jamming, and being an unwelcome nuisance. They tried changing the CTCSS tone a few times, but the bad apple was able to follow them. They switched to using DCS and that stopped him. I'm not sure how close this story is to the truth, but I am certain that the repeater is using DCS, because I've used the repeater. One interesting thing about DCS: Most ham transceivers are set up so that, if they transmit DCS, they will only receive transmissions with the same DCS encoding. Unlike the way CTCSS is usually implemented, there is no option to encode DCS without requiring it for receiving. I don't do crossband repeat, but if I did, I think I'd use DCS 0n the UHF side, to make it less likely that someone would stumble upon it and unwittingly get into my crossband repeater and bring up a wide area 2m repeater.