Can't speak to the past, but currently we have issues with young potential recruits being denied due to their honesty.
These poor kids are being told in school its ok to be 100% honest with their mental health and its all fine, with the result being them getting eviscerated in the real world which doesn't work that way. The CanadianForces asks a question along the lines of 'have you ever thought about or attempted committing suicide'. If they answer 'Yes' their application is dismissed. Many of them would actually be excellent recruits, but due to one question many are rejected. The other big hang up for most of them is passing the fitness test, which even though my out of shape body can pass with ease, somehow these teenagers can't.