No prob. Even though an arc can’t be sustained at 12 VDC, the arcing could still be substantial, simply because it’s DC. If the switch has a slow contact spreading velocity due to a “slow break” mechanism, it might be adequate for AC but not for DC. (“AC only” switches tend to have slow or indeterminate contact spreading velocities. DC and AC/DC have quick-break mechanisms.)
Remember those old DPDT slide switches? The contact spreading velocity was determined by how quickly you slid the switch. Fine for certain AC applications. Not fine for DC.
BTW, my responses in this thread are “on the record” responses, the same as I would give to my customers at work. Off the record, the switch will probably work fine at 12 VDC / 3 ADC, though I don’t have hard data to back this up. Hence my reason for being cautious.
High frequencies become effectively like DC because it takes a short time for the air to deionize*; this time can be an appreciable fraction of a second at very high voltages (0.3 seconds for 275 kV), also strongly dependent on many other factors like current and gap length (as shown in previous posts, like the example I used, 50/60 Hz AC can easily arc over considerable distances).
*This is also why electronic ballasts get more light output from fluorescents for the same drive power; higher frequency, up to about 2 kHz, reduces the time when the gas isn’t ionized.
It will probably be O.K. Just make sure you install a snubber diode across the load. A 1N4007 should do the trick. May also want to install an RC snubber across the switch contacts.