I haven't pushed aeration in the past because I'm not set up to do it very quickly. Any I get I just sub out. I have been leaving it up to the customers to mark any obstructions on their own. My question is this: do you ever have problems with phone/cable lines when you are pulling 3.5 inch plugs? I have seen how these guys bury the line, and occasionally even hit one with the skidsteer when we are prepping lawns.