(Warning; Bourbon induced syntax)

I am fairly new @ World and already I have been hit up for giving LOR's. A friend had given me one and I would certainly like to pay it forward. However, I have found one should be selective as to whom they recommend. If one or two turns out to be bad then you reduce the efficacy of any future recs. Not to mention, I am sure my employer wouldn't put much stock in a probationary employee's recs.

Someone you know is a great pilot but has an attitude problem. Or, you know someone with a great attitude but haven't flown with them. (World wants you to have flown w/ the candidate) Sometimes I feel torn. I really do want to help but, I fell have to cover my own butt. I have even been "cold-called" for LOR's through these message boards. i.e. "Hey, would you be willing to get to know me via email and write me a rec?"

How selective are you when giving recs? As for negating your recs if you recommend one that didn't work out, how does your airline look at LOR's?