You don't want to share the balloons so you hide them, but is hiding them safe?
What else can be done to keep something safe? It can be locked.
The locks can be picked. An example is my car. A few days after I bought it a man showed me how easily it can be opened using a scale and sold me a solution that would prevent it. I bought that and a gear lock too for peace of mind
A few years later I locked myself out of the same car with that “security feature”. A man took a wire, twisted it to make a hook and opened the lock in less than a minute. (He was a only a driver, not a professional car thief)
My car is safe not because I have used measures to keep it safe but because no one has stolen it.
Considering this, I guess the best way to keep something safe is to keep it hidden.