The pressure regulators themselves are cheap and let you use any of the dripper / dripline / drip tape / spray / spin watering gadgets. Maybe some of those could do some of your basic watering, and then you could add water by hand where needed.
http://www.dripworks.com/categ...
My thought was just that it might keep someone's flexi-hose from blowing up so quickly. Especially if the hose advertises a recommended average pressure. All I found in a few minutes of searching was something like "burst strength 200 PSI" and "withstands 250 PSI".
If pressures are an issue, one thing you can do is reduce 'water hammer".
When water in a pipe or hose moves at its top speed, it has both pressure and inertia. If you stop the flow by just letting the spray nozzle snap closed quickly, the water "tries to stop instantly". The water right at the nozzle HAS to stop since the nozzle is closed. but now all the water behind it rams all it's inertia, flowing at perhaps 5-15 feet per second, at the water stopped near the end of the hose. That creates a big pressure spike that pushes back on the speeding water and slows it down within a second or less.
When you slam a valve closed in a chemical factory with 3 inch pipes and very rapid flow rates, you make a huge noise and vibration. You might break things or burst pipes and see them tear themselves off their mountings due to vibration and flex ("water hammer"). You have to close those valves slowly so the water can reduce its speed and momentum in response to much milder, more gradual back-pressure.
