Aside from the insanely high prices, I'd say it's probably safe as long as it's a listing like this one:
http://www.amazon.com/Biohazard-Resi...9639746&sr=1-2
Clearly marked as an import, label info lists a legit Japanese publisher (in this case, Suleputer), and your order will be shipped and/or fulfilled by Amazon. If a listing meets all three of those, you're pretty much safe. Anything less and you're taking a risk. The "fulfilled by Amazon" is the most important part because if you do get a bootleg, you can simply return it for a full refund due to their "product received did not match product listing" return policy.
Also interesting to note with that particular listing is that the ASIN (B000Y3JG44) matches the one on
Amazon.co.jp's product page, so that might be another thing to check.