This is probably why:
Republican National Convention presidential vote, 2008
Candidate Votes Percentage
John McCain 2,343 98.45%
Ron Paul 15 0.63%
Mitt Romney 2 0.08%
Delegates that did not vote 20 0.84%
Source: en.wikipedia.org...
For arguing purposes, let's say each delegate represents a certain amount of people that ends up totaling the entire population of the US. If you
follow the number
here, there are 305,071,070 in the US. 0.63% of that is about 1,921,948
people who, despite overwhelming support for McCain, still resisted and voted for Ron Paul. Although that is small, for somebody who is a "fringe"
candidate to receive even that much can be frightening for them, since Ron Paul supporters are known to be the most active of all the supporters.
All the Secret Service is doing is making sure that the number doesn't grow anymore. Does it make any sense to take Ron Paul stuff from delegates?
Probably not, but it shows their desperation.