[wcc]

No, there is no etiquette. But what you could do is talk to your neighbors that are doing it. No I don't mean to go ask them nicely to change their ways. You gotta be smoother than that. I had this exact problem with one of my neighbors and I talked to them and it worked.

When I saw them out in the yard I went over and asked them about lawn care stuff, fertilizer, seed, etc. Personally, I could care less but I listened to them. Then tell them you think you have grubs eating your grass and you did some research on them on the internet. They'll give you their input. Then you say during my research that you found out that watering your yard between 1-5am is the ABSOLUTE best time to water and you are thinking about putting in a underground sprinkler for that reason. Ask them if they ever tried it. If not they should cause what you found on-line is it makes your yard greener and healthier, blah, blah. During your conversation just keep mentioning that 1-5am is the prime time to water. Doing this changed the ways of my neighbor with no hard feelings. Give it a try. It might work....