I always let the capship driver decide what happens to their ship, be they friend or foe.
Wording such as "We inflicted heavy damage on the enemy cruiser, but could not confirm the fact that it blew up or not.", "I did not witness the end of our battleship, but I am sure captain X's piloting skills recovered it mostly intact." "When I lost contact with the enemy battleship at the edge of the nebula, she was severely damaged, I imagine she will be dry-docked for an extended period of time." to give but a few examples, leaving the other guy to decide if his ship made it home intact, or if it was abandoned in the void (which can potentially make for some good RP).
Fighters are much easier to deal with-the pilot simply ejects and is tractored by his comrades...many's the time I've flown home with seemingly the entire SCRA in my hold...:P
As for posting kill messages in message dumps and the like, I feel it is unnecessary. If high command cannot believe the reports of it's pilots, what sort of high command do we have? A pilot's word is his honour, if he gives it, it should be respected as such.
Excessive "blue message posting" just looks, to me, like an attack on the other faction's players. Sure, take screens of their demise and keep them as souvenirs (I like to count the number of kills I got on my Xeno Preagle in 4.84 (something like 60-70% of all the kills I have...)), but there's no real reason to wave them all over the forum (I have one or 2 screens of me getting the kill message on The Necrosis, but you will not find them posted anywhere...I see no need to).
Bounty posts are the one exception I take to this rule of thumb, as there is an actual cash transfer involved...fortunately, all my Bounty Hunter/Mercenary characters tend to make rather succinct reports, meaning I don't have to worry about exactly what happened to their ships/them, and that is their choice.
Essentially, leave the particulars of each player's demise to the player in question.