This is a diabetic's best friend. It is discreet enough that it can be inserted easily under a skirt - or even loose pants, if you place a cardi/blanket over yourself. If you're female, you do need to stay very still whilst using this, as the 'funnel' into which you pee, is made from hard plastic and is narrow and rigid, so if it jostles, there is a small chance of a leak. Guys won't have this problem, unless they end up overflowing the bag, which would be pretty hard, as holds a full 800ml of liquid. The bag does get quite heavy when full, so keep a firm hold on it!
I tried it in a parked car, on my knees facing into a front seat, wearing a skirt and no-one was the wiser. What's great about this is that the granules absorb the wetness, leaving no chance of any leakage and virtually no odour. You just need to drop the filled bag into a carrier bag for later disposal.
You get 3 wees per pack, and to be honest, if a child hasn't filled up an entire pack, it could be re-used the same day; certainly don't keep this overnight. You also get a wet-wipe per pack, which is handy if you've forgotten to pack any/there are any spills. Do take care unfolding the plastic bag from the funnel, as a tear in the wrong place doesn't bear thinking about!
A bit expensive, perhaps, but a life saver on long car journeys or where public loos are beyond use. The only thing I would change, would be to make the 'funnel' a bit longer and wider, for added peace of mind.