I spent a summer issuing permits in Yellowstone and am close friends with lots of NPS Backcountry Office staffers.
First: Neither I nor my friends have ever denied anyone a permit for perceived danger. In fact, I was explicitly told that I couldn't stop someone from doing a hike they wanted to do as long as the sites were available and the visitor listened to 'the spiel' (bear safety, river crossings, etc.). Of course, I'm a lightweight hiker who puts in long miles, as are most of my friends, so we're open to pretty much any trip idea.
However, I've certainly run into skeptical Rangers who looked at me like I was a crazy fool and asked a lot of questions before finally, begrudgingly issuing the permit. I feel your pain.
Issuing permits is tricky. While it's ultimately not your job to stop anyone from doing what they want to do, you have experience with people venturing into the park and getting hurt. You and/or your fellow Rangers have likely participated in long, grueling, potentially dangerous search and rescue missions for just such people. And when you only spend 10-20 minutes with someone in an artificial situation, it can sometimes be awfully hard to tell someone who has the experience to pull off big trips from someone who doesn't.
Luckily, however, people often self-categorize by asking certain types of questions, mentioning certain details, etc. "Yeah, I was planning on crossing X River and heading up Y Pass" with no apparent knowledge that X River is literally impassable on foot that time of the season—that kind of detail raises a red flag. You try to help the visitor realize not only that X River is impassable but also other important facts. Many people take this advice, realistically judge their own experience and abilities, and reassess their plan. Some don't. In the end, a good BC Ranger should only be trying to maximize visitors' overall safety and experience.
The difficulty is that it's a person deciding what sounds reasonable and what doesn't, and we all have different opinions about these things. This is unavoidable.
As to whether or not to lie: Most parks won't initiate search and rescue. They'll usually take down some information about you—tent, pack, and rain jacket color and general physical features come to mind—but not keep a record of your exact route. It's your job to make sure someone you know has that information and knows when to initiate S&R. If you don't have questions for the Ranger and feel confident in your ability to do what you're requesting permits for, I don't think you have any responsibility to provide more information than the bare minimum required. If the Ranger seems very unreceptive, I think fudging's just fine. I've certainly done it.