Staying at a hilton property on a government rate when traveling for leisure may be problematic depending upon the ethics rules of the governmental body and on how the property feels about it. Most seem to not care as they don't even ask for ID let alone travel orders or documents, on a rare occasion I have gotten an extended inquiry about my use of the rate. Some properties have dealt with this issue by setting special leisure rates for government employees. I have found this leisure travel government employee rates most common at Doubletrees.
GOVERNMENT GETAWAY
Save 15% off Bed & Breakfast Rate. Includes breakfast for up to 2 adults and 2 children ages 12 and under each night of stay. Valid Government or Military ID required at check in. Rate valid for leisure stays and not official Government or Military travel.
The rate above ends up being about 10% less than the official state or US government travel rate.
In my opinion, danger's friend should inquire further as to the availability of that particular rate for his friend's circumstances.