I have had several contacts with what I initially thought were ham stations in the 6 meter band only to turn out to be Military stations throughout the US and even one on 53.35MHz being military out of Mexico.
Some of the more popular ones that I hear yearly are 50.00, 53.35MHz, 50.6 MHz and 52.500 MHz which are commonly heard Mil stations picked up during the past seven sparodic E-seasons in Northern Oregon.
50.00 FM is probably the most heard and logged for Mil traffic, and it is frequently heard around the US and Canada.
In fact during the past 7 sparodic E-seasons, from may to July, 50.00 MHz has even been posted numerous times on the ON4KST 6 meter dx cluster page as being a very busy military frequency.