The 'malicious' bits are typically covered by good shareholder agreements, the ones with teeth in them. Angel investors that intend to 'do tricks' tend to bail out when they come across terms like that so a good shareholder agreement not only serves you well for the shareholders themselves but can also serve as a filter for prospective shareholders. Of course the more angel investors you have the bigger the chances that you draw someone who does not have your interests at heart. So you will still need to vet them, the easiest way is to contact founders of other companies they've invested in. With a lot of first time angels flooding the scene this is of course not always possible.

A good way to deal with having a lot of angel investors is to create a separate 'angels' vehicle where angels participate, this vehicle then participates in your company.

That way you have all of the benefits and none of the drawbacks of having a lot of smaller early stage investors. You can roll your 'friends and family' round if you have one in there too.

Edit: Ah, the author mentions the 'roll-up' vehicle at the end of the article. Good.