In Econ, the latter is called differential pricing and there is nothing evil about it at all.
http://www.pricingforprofit.com/pricing-explained/differenti...
http://www.pricingforprofit.com/pricing-explained/differenti...
We sure as hell _experimented_ to see if the decrease in conversions by bumping margins (and hence prices) up was worthwhile in terms of total profit.
I'd happily make an argument that if the first is morally "OK" then so is the second…
Did you also test a popup saying "Hi, you're a first-time visitor to our website, we can discount this room rate 10% if you book today"? :)
They are instead offerent more expensive hotels to Mac users - on the reasonable assumption that Mac owners are higher spenders compared to somebody connecting from a free PC in a public library.