These forgeries are in fact easily detected - the signatures of the Cardinal Secretary of State have small errors and the seal is clearly not an original seal, neither is the paper original nor the recording number on the reverse. Most telling is the fatc that the names of none of these recipients are included in the Acta Apostolicae Sedis, which publishes the names of those who have been honoured by His Holiness.
There are even organisation for the recipients of these worthless "honours", called the Royal College of Papal Knights in the Americas otherwise more modestly styled the College of Papal Knights (see http://www.papalknights.org/college.html which lists the officers, all of whom bear invented titles. One of the members of this so-called College has been accused of allegedly selling fraudulent stem-cell treatments - see http://www.sitejabber.com/blog/2010/09/02/weekly-scam-alert-stem-cell-treatment-scams/
Below some fake diplomas: