Really, it wasn't just 'The Minister' that wanted her opinion, it was Kingsley, which made all the difference. Despite what Percy thought, Hermione really did respect the man and wanted the Ministry to be a respectable place as well. Removing suspicious employees seemed to be a good start. If she happened to mention the Saint Patrick's Day party coinciding with the journal incident just to see what Kingsley had to say, then that would just be for interest's sake.
Shrugging in initial response to Ron's question, she glanced back at him. "I think you could have mentioned you might be late, or you had a meeting outside of your normal hours. Even if you didn't know what was going on or how long you would be, you did know you weren't going to be home on time."