For example, the exchange rate on BTC-e during the Bitcoin crash the past few days hardly changed. It was around 0.02 BTC per LTC before, and it's around 0.02 after. What did change is the USD per LTC, which dropped from $4.60 or so before to the $1.90-ish yesterday and now $2.50ish today since Bitcoin's value is increasing again
They stayed at such similar ratios because they both fell in value together at similar rates. Had LTC actually been disconnected from the price of BTC, we would have seen a very different LTC/BTC price than we saw before the crash.
Right, exactly. The value of LTC dropped as well. I think that right now people tend to consider them too similar to really treat them differently.