Ah, such is life. :(

[Draglin Stoneshield]

[Ubundi]

If you want to improve your app selection process I would suggest go guild website hopping. Most Guilds have their app proceedure on public display. Find the style of guild that you would wish to emulate abd maybe chat to some people in that guild (doesnt have to be on your server) as many peeps have an email address on the website.
As for the specific question of should someone be able to spend their DPk or whatever you call it before leaving, I would say yes, they have the right to spend this how they wish. As for anyone sayng that they have a right to stay and use the item for the benefit of the guild I would reply that they have aided the guild and provided their time and effort to the gain of all those people who have gained loot while the individual didnt previous to this. They were recompensed with DKP to spend at a later date. If it is a critical item at the cuting edge of whatever you are doing then maybe you could have announced in /rs that if the specific item drops it goes to a specific player for <insert reason> and its done before the raid starts then that could be considered acceptable. outside of this then you are obliged to follow the loot rules that have been published and agreed no matter how you dislike it.
It can be hard when it happens but unless you wish to go through you time in the game getting a bad rep from those individuals who may be in a guild you wish to join, or others in your guild wish to join, at a later date then accept it happens.

[Grokii]