Can you select role which gives you money but you can't use it in Puerto Rico?

Question

I have a situation where a player chooses the Trader because it has 5 coins even though he has nothing to sell in the trading house. Can he do it?

Answer 1

Taken from the rules:

Implementing the action of a character is voluntary (exception: Captain)

Note: You can still choose Captain if you have no goods, the exception just means that if you pull Captain and have goods, you have to ship.

Answer 2

Definitely

Choosing a role merely for it's privilege is a perfectly valid move. It may not always be wise to choose a role you cannot fully take advantage of but if you are really short on cash such a trade off may be warranted...