Content Protection will make EA's take an extremely long time to finish as it encrypts every piece of data as it comes in. Same thing goes for wiping the device as well.
Depending on how much data a person has the longer it takes. Also, if you enabled the 'Disallow third party application downloads' policy, there is a better way to do it. Disabling downloads does not stop someone from connecting a BB to a desktop with DTM and installing software.
I would use this instead: BlackBerry Search Results
This a lot more secure and you have all the control with this. Essentially you block all application installs. It creates a software config to Deny at the top level. Then you just add the apps you want to allow in your environment.
Hope that helps with your security.