Morningstar argues that because ETF managers' personal investment goal may be different than the ETFs', it is not necessary for them to eat heir own cooking.

The result was disappointing. For most of the funds I checked, few of the managers had anything more than a token amount invested in the ETFs they ran, according to their funds' most recent disclosures with the Securities and Exchange Commission. The managers of Barclays Global Investors' iShares and State Street Global Advisors' streetTracks and SPDR ETFs had no money in their funds as of their most recent disclosure, while managers at Vanguard and PowerShares had at least some money invested alongside their shareholders. Of those firms, only Vanguard linked manager bonuses to the performance of funds they ran.

Should this matter? After all, most ETFs are market (or market segment) tracking index funds that are extremely tax efficient on their own, so it's not like an ETF skipper needs incentive to beat the market or manage taxable distributions.

I think it does matter, though, for the same reasons it matters for conventional open-end funds. Simply put, the interests of managers who are compensated based on how well they run their funds, and who have significant sums of their own money invested in their portfolios, are more aligned with their shareholders. Whether a fund is active or passive, exchange-traded or traditional, managers are more likely to ensure a fund delivers what it promises for a reasonable fee if their own wealth is on the line.