When tying up to a dinghy dock, it is important to know that the line you use to tie up your dinghy will both hold your dinghy in place as well as be tied over and under other peoples bow lines.
When you tie up, you will be tying up to a cleat that is used by many many people; all holding a variety of dinghies up to the pier. Should your tying fail, your dinghy will drift away! This means that not only do you need to tie up well to secure your dinghy, but you risk the holding of your dinghy to the tying skills of others.
If you tie up to a popular cleat, anyone who was there before you will need to untie your line to be able to untie their line. Then, you hope that they tie your line back up in a proper manner. This is where you risk losing your dinghy!
Instead of tying a standard cleat hitch over the cleat and over all the lines of other boaters, why not tie a bowline through the cleat below everyone else? This will allow everyone to tie and untie their dinghies without ever affecting your knot.