What do you mean by tickle the player? ... And how not going in screen saver mode can burn-in the screen (sorry didn't know about burn-in just googled what it is)?
By "tickle" i mean to simulate someone pressing remote button to keep it awake. Roku has this feature
that allows limited remoting over network. I have read on the forum in the past it being exploited in the way suggested - the channel making a round-about network call to the player and injecting button press to keep it from falling asleep. You won't need to deeply understand the protocol for this, can just use snippets we gave.
No need to freak over screen burn-in, it's just that TV screens (CRT, plasma, OLED... actually seems all types) are prone to permanent discoloration of parts of the screen if the same image has been shown for really, really, really long time. See wiki page
for examples. There is no special magic by which designated screensavers prevents burn-in, they are just written to show moving images on mostly black screen - you can do that on your own too, just don't leave same image on screen for days.
There is also the part where Roku player goes to deep sleep and turns off any video output. I don't know how that works (does anybody know?) but assume that after a screensaver has been on for long enough (=?) time, it is lights off even for the screensaver.