[Ian J]

I'd also like to add that if you have flight following in a "practice area" where the controller expects you to make many altitude and heading changes for training purposes you should still tell them if you're doing anything whacky. I was doing power-offs one day and decided to take my student almost to landing at a grass-strip. We did a recovery at about 100 ft AGL and as we climbed back up ATC called up a little concerned because we dipped below radar coverage and he thought we went down. Lesson learned for me.