Had my first hostile encounter while my sole jump-capable scout, the SC Magellan, was exploring a system two jumps away from Sol: V1581 Cygni.
At first, the ship detected the source of some active sensors with considerable range (strength 33600, resolution 100). The Magellan was a few million km out of its range, so I told it to stop dead on her tracks and wait and see if her passive sensors gathered any valuable information. It'd ultimately be a Bad Idea(tm).
Four a half hours later, approximately 30 vessels (presumably fighters, given their numbers, very light weapons and how late they were detected) appeared on the Magellan's sensor screens. Not a second later, they opened fire on the scout ship, crippling it in a single pass. The fighters seemed to be equipped with one meson cannon each, with an observed range of 60,000 km. They may be a threat even to my frigates, given the meson's armour-skipping properties.
So given the Magellan ended up completely disabled, I instructed the crew to scuttle the ship (deal 100 damage to herself), so that neither the crewmen nor the ship ended up in enemy hands. I didn't want the aliens to scoop up free Terran technology. Unfortunately, the Magellan's captain and 45 others made it to the lifepods. There's no hope for rescue, so the pods will invariably fail within 13 days.
If I'm lucky, the survivors will die before they're captured. I hope the vile aliens get nothing from the Magellan's wreck!