Questions about Ebay

I've recently done some shopping on Ebay and Yahoo Auctions and was wondering about your view on the following:
1. If you see a deal that seems really good, and you try e-mailing the seller, and get zero reply from him, would you still take the risk and just go ahead and bid? I recently saw an MP-04 that looked like a bargain, messaged the seller to confirm if it was MISB as opposed to just MIB, and had no reply. Another had an exorbitant shipping to Singapore price, even though he claimed he's in Singapore, and I wrote to ask if there was a mistake there. No reply.
2. Of late I've also seen this BS clause, where a seller will write that he isn't responsible for late delivery, lost packages, etc. He however does not have an insurance option. My question is, how do I know the rotten SOB posted the item at all? I could have paid him, he claiming he's sent my toy to me, and 6 weeks later with zero arrival, just say that it was probably lost in the mail. Not his responsibility. Would anyone still buy from a seller with a clause like that? And any steps can be taken to safeguard yourself?
Thanks!
1. If you see a deal that seems really good, and you try e-mailing the seller, and get zero reply from him, would you still take the risk and just go ahead and bid? I recently saw an MP-04 that looked like a bargain, messaged the seller to confirm if it was MISB as opposed to just MIB, and had no reply. Another had an exorbitant shipping to Singapore price, even though he claimed he's in Singapore, and I wrote to ask if there was a mistake there. No reply.
2. Of late I've also seen this BS clause, where a seller will write that he isn't responsible for late delivery, lost packages, etc. He however does not have an insurance option. My question is, how do I know the rotten SOB posted the item at all? I could have paid him, he claiming he's sent my toy to me, and 6 weeks later with zero arrival, just say that it was probably lost in the mail. Not his responsibility. Would anyone still buy from a seller with a clause like that? And any steps can be taken to safeguard yourself?
Thanks!