Actually, that's not entirely true, about the LDS Church not having an excommunication policy. They actually have a very aggressive excommunication policy. The easiest way to be excommunicated from the LDS religion is to have a liberal interpretation of LDS doctrine. Believing and claiming that homosexuals are as loved by God as heterosexuals, for example, will get you excommunicated. So will questioning any of the claims of the church, such as the very standard egyptian burial diagrams at the end of the Pearl of Great Price which are described in the book as depicting the sacrificing of Abraham's son. Several professors at Brigham Young University have been excommunicated recently for reasons such as these. You can also get excommunicated by consistently failing to repent for sins... Heck, many of the original members of the LDS church were excommunicated at one point or another, including three of the eleven witnesses who claimed to have seen the golden plates the Book of Mormon were "translated" from. Interestingly enough, of the eight remaining un-excommunicated witnesses, five of them eventually left the church.

BTW, for the curious, the historical excommunication info presented here is church history, taught to LDS children.

Response to karrenlouise-
Ok, on the first point, I may have been a little short on my explanation. I know people who were excommunicated for preaching that homosexuality was NOT a sin. That they were excommunicated is fact. I realize I was vague in my original statement, however, and for that I apologize. I know people who believe very much in the LDS religion, and also believe that god accepts that they are gay, and that it isn't a sin. They are extremely distressed at their excommunication and constantly talk about changing views in the LDS church, hoping that they will be allowed back in. I think another friend said it best when she snapped and yelled at them "You don't understand, they don't want you!"
As for the second point, I never claimed that they denied their testimonies. You are correct, there is no documentation of them denying their testimonies that they had seen gold plates.

The LDS religion is an often unjustly maligned religion. I'm not anti-LDS any more than I am anti-organized religion. See mormon girls for an example of my neutrality on the matter.