The attraction of cap and trade systems is that they provide a more certain environmental outcome (a set level of allowable emissions), but at the cost of price volatility.

WSJ: The Experts: Should There Be a Price on Carbon Emissions?

However, if you are a significant shareholder of a smaller-cap company like wireless connectivity provider iPass (nasdaq: IPAS - news - people ) and intend to present a legitimate resolution at the meeting to unlock shareholder value, the cost of getting to California for the meeting would be an allowable deduction.

FORBES: Most Overlooked Deductions