The Stars are not exactly Fair - mind you - even a 2 star or 3 star trade can be unfair - take for instance a Cross-Tier trade from Tier 3 to Tier 1 at 0.06 ratio - this is an unfair trade 1,000 (Tier3-goods) for 16,000 (Tier1-goods) but the trader says it is a 2 star trade of equal value - it isn't equal value when you consider the space requirement per square and all the other factors involved in the trade (Population*Culture*Workshop*etc...
I myself when making Cross-Tier trades perfer to give "value" to not only my Fellowship but also to my World Map neighbors i make a trade like this for example:
These say they are 3 star trades but still you can't go by the Star Trades in Trader as it just isn't fair the way they have it set up - look at the numbers which would you take a trade for:
current Trader for 2 Star at 0.06 ratio
1,000 Elixir for 16,000 Steel
or mine as i set up above that i offer