I think you want to be careful with offering solutions that would appear to be at least in part financially motivated (such as directing people to a commercial site). Ideally, you would build in the cost of making transactions safer into your operating costs, as opposed to passing it down to the user. This is of course challenging when you are running a for-profit.
P.S. hope you know what I'm referring to (would not name the specific commercial site on this blog); please email directly if you'd like more of my input in the future -- I find Victor Sage's emails... well, PRish... which is to be expected, he appears to be a hired PR person after all.