Consideration:
careful thought or deliberation
something to be taken into account when weighing the pros and cons of a situation before making a decision
detailed discussion or scrutiny
http://encarta.msn.com/encnet/features/dictionary/DictionaryResults.aspx?refid=1861599737
Courtesy:
consideration, cooperation, and generosity in providing something - as a gift or privilege.
general allowance despite facts
http://www.merriam-webster.com/dictionary/courtesy
Consent or agreement in spite of fact; indulgence.
They call this pond a lake by courtesy only.
Willingness or generosity in providing something needed.
They received free advertising through the courtesy of the local newspaper.
http://en.wiktionary.org/wiki/courtesy?rdfrom=Courtesy
A kindness, favor, help, or generosity beyond normal limits of rationality.
However, coutesy also has one meaning of doing or performing some thing as a matter of protocol.