Doping is a problem that should be stamped out but I think that some of the restrictions are too prohibitive.
I think what happened in the case of Rodrigo Pessoa, the Olympic Committee was going a bit too far. The amount of "dope" found in his horse was not enough to affect the animal's performance in any way, and could have been accidental! The people out there who knowingly commit doping offences definatly need to be shut down, as it is unfair to the competitors who put their all into a sport and play fair!
I hope they come up with guidelines reflecting at what point banned substances are actually affecting the horses' performance. In many cases, mere traces of banned substances are part of legitimate medications that don't affect performance in any way. Perhaps some determination of lower AND upper limits are in order!