This is my way to detect search engine bots quickly with C#. do u think is accurate?

I was looking for a way of finding good search bots without going through huge list of User-agents.

This is the code I came up with:

string userAgent = HttpContext.Current.Request.UserAgent.ToLower();
string[] botKeywords = new string[10]{ "bot", "spider", "google", "yahoo", "search", "crawl", "slurp", "msn", "teoma", "ask.com" };
int n = 0;
foreach (string bot in botKeywords)
{
if (userAgent.Contains(bot)) n++;
}
bool isBot = (n>1);

What do you think?
Is it accurate? How can this be improved?

Thanks

Sorry I didn't explain the code for who doesn't know C#.
In practise if the User-agent contains any 2 or more keywords from this list ("bot", "spider", "google", "yahoo", "search", "crawl", "slurp", "msn", "teoma", "ask.com") than it's considered a bot and probably a search bot.
I did this to have a way to find bots and make this durable also in the future without having to update any list.