I have several thoughts on this:

1) Whenever a buyer tells me something is damaged i ask for pictures – I do nothing further until I receive them.  If I don't receive them it means it wasn't really damaged and the buyer was just pulling a fast one.  If I do receive them I check to see if they are really damaged or if the buyer is complaining about something as silly as a fingerprint on the blister or tiny scratches when held under a magnifying glass – stuff along those 'ridiculous' lines.  If it's a silly reason, I let them know they can either send them back to me for a replacement (they pay return shipping AND they pay for me to ship out another set of cars).  Or, they send it back to me for a refund and I don't refund their shipping. 

2) I would NEVER send money to 'compensate' someone while at the same time letting them keep the cars.  That's an old trick that scammers use to keep the item and get money back to lower their cost as much as possible. 

3) If the item is truly damaged I do help – I don't believe a seller should just wash their hands of it and say "too bad – it happened during shipping".  That's a great way to build a bad rep and get negative feedbacks on ebay or on the boards.  You need to help correct a situation if the damage is legit.  I sold a case to a guy that was double-boxecd and when it came back it looked like it had been run over by a truck or used as a stepping stool for some postal worker.  It wasnt' his fault – so I sent him a new case and sold off the damaged one at a discount on ebay.  Yes I lost some money but it was the right thing to do.

4) I disagree with those that say to take photos before you ship it.  Realistically will you have time to do that?  I ship 15+ items a day, I have no time to photo everything with before, during, and after photos of the cars going into the box and then catalog/track them on my computer.  Plus if it's damaged in shipping those photos really won't do me any good.  Buyers are usually sided with during ebay and paypal disputes. 

5) As a buyer I'm much more picky but I think I'm fair.  If someone says MOC it better have 4 crisp corners, and no creasing.  I had a thread on CTT called 'Damaged and Returned Items' – you can see some of the crap I received my bad sellers that I had to send back.  My favorites are those that don't even use a box and just throw it into a manilla envelope.  Or the guy who put his personal notes and scotch tape on the blister completing ruining it.  Or the guy who folded the deluxe card in half to get it to fit into a smaller box. 

Got to be careful with that – as a carded collector I don't want anything marked up – it destroys the value of the item and lowers it's value.  I bought a car from a seller where I noticed he had done just that and I returned it to him because of it. 

I've filed both paypal and ebay cases as a buyer and I've never lost – even when the seller shows photos of what he sent me.  Now, I've never pulled a switcheroo and never would but if I order something and the seller doesn't pack it with common sense (i.e. throws it in manilla envelope instead of box, folds the cardback in half, or describes something is mint and it arrives with tears and creases) then I return it and ask for a refund.  If they refuse I file a case.  And I don't care how it left their hands and what photos they have, cause if they didn't pack it well it's not the shipping company's fault and it certainly isn't mine.  I've never lost a case yet.  Both the ebay and paypal policies are very much slanted in terms of the buyer as it should be. 

My point is that you can go through this huge exercise of photographing every item you want, cataloging them, tracking, them, and mark them with pens.  But in the long run you will still likely lose any case in which damage is claimed.  The seller has a responsibility to deliver in good condition the item the buyer purchased.  So if your only defense for a case is "it left my hands in great condition – see my pictures" that's not enough.  The pictures will help you win a 'switcheroo' case where you send someone a super chase and they claim you sent them a Lightning McQueen or that the box was empty.  But pictures are not going to win you a damage claim in which the damage was legit and occurred during shipping.  Just as a tie in baseball goes to the runner, a tie in a ebay or paypal case goes to the buyer.  I know this cause I have been on the buyer side of these cases.  I dont' claim fictitious damage but if it's a mess when I open it the seller is sure not going to pin that blame on me simply because he had photos.