Oh, and I should have added, when asking your packaging questions before the auction ends, and especially if you have reason to message the seller again after it ends if you are unhappy with something (crap packaging, item having damage not visible in the photos or otherwise not as described, etc.), ALWAYS use eBay's own emailing / message system to communicate with the seller. Never be tempted to email them personally outside of eBay, even if they reply to you that way. Keep it official and on record with eBay, and no matter how tempted you might be or how provoked you feel by their bad behaviour, always keep your messages factual and to the point. Never insult or threaten the seller, even if they are rude or do so to you. Firstly, you catch more flies with honey than vinegar and if the seller can be persuaded to do the right thing themselves, it usually saves you a bit of hassle. However, more importantly, secondly in the event of a dispute arising and the seller being a complete asshole about it, make sure eBay have a very clear record in your message thread of a polite, reasonable and hard-done-by buyer, who had the misfortune of buying from an unreasonable, lying, incompetent fuckwit. You'll win every time.
One last point about the initial questions you ask about the packaging before bidding; never assume anything! Just because the postage charge is high, low or middling means absolutely nothing! Unless the auction very clearly states how the item will be packaged for posting (and quite frankly, why wouldn't you want to reassure buyers of a high-value and or easily damaged item that they are safe to buy from you?!), always assume the seller hasn't got a clue about packaging and ask your questions. As Mini99 and Edd both say, educate the seller and risk patronising them by asking what really should be an insulting question to them, if they know what they're doing.
Some examples I have used are things like:
"As you may know, with Vintage Star Wars toys the condition of the box / packaging is usually more important than the toy. Any damage decreases the value. Please can you confirm how you will package this for posting, to ensure the toy cannot rattle about inside its box and damage either itself or the Star Wars box, and also how the Star Wars box itself will then be packed for posting to ensure it cannot be damaged in transit? Will you, for example, carefully pack out the Star Wars box with clean plastic bags, tissue paper or bubble wrap (with no tape on it) to stop the toy from moving, and then carefully pack the Star Wars box in a much larger, very sturdy double-walled cardboard box with several inches of clean, tape-free padding on all 6 sides of the toy's box? Having no tape touching the toy's box is very important as it can damage it."
"Will you, for example, send this figure protected inside a Star Case, with that then bubble-wrapped and packed in a much larger, very sturdy double-walled cardboard box with several inches of padding on all 6 sides?"
If the seller gives a damn, they will reply and reassure you. If they don't, they won't. If they do reply but say something along the lines of 'This will be well packed inside a Jiffy Bag', you can either try one last time, politely spelling out that item will get damaged that way and any buyer will likely return the item to them as a consequence, but that you will be willing to bid if it is packaged as you previously described, or else forget about bidding on that particular auction. It may be the most desirable item in the world, but if it's not going to arrive in the condition you want, it's as good as bidding on a damaged one already.