Is it permissible to take one’s Monroi to the bathroom during a game (ostensibly so that it doesn’t get stolen)?
What about taking one’s paper scoresheet to the bathroom?
Is there a difference?
Is there a rule about this?
If I"m not mistaken the rule re: electronic scoresheets is that they must remain at the table.
That makes sense, since paper scoresheets don’t have analysis engines… 
Both types of scoresheets have the same analysis engine (a brain external to the scoresheets themselves). A difference is that the electronic form immediately allows you to look at various positions, enhancing the effectiveness achieved using that brain external to the scoresheet itself.
Neither scoresheet (electronic or paper) should be taken out of the playing area! To begin with, the scoresheet is the property of the sponsor of the event (See Rule 15G). Of course, I interpret that to be while the game is in progress. If the sponsors requires that a copy of the game be submitted by the players, duplicate scoresheets must be provided.
If I see a player taking the scoresheet out of the playing area while the game is in progress, I direct him or her to take it back.
A few years ago, during the third round of a five-round event, I had a player who took his scoresheet to the bathroom, and from there went to the skittles area and proceeded to analyze his game (still in progress). I was alerted by another player, so I went to the skittles area and calmly grabbed the scoresheet from which he was analyzing and asked him if he was still playing. He looked puzzled and, without much choice, replied that he was, so I told him “Not anymore – your game is done! And, by the way, you are also done with the tournament.” He did not object…
I assumed that one would not be able to take a Monroi to the bathroom, so let me follow up with this question…
Do organizers’ insurance (assuming they have insurance) cover items stolen from players during the play of a tournament? I remember back in the early 1980s, it was not uncommon for clocks to be stolen from tournament rooms.
I’ve left my Mon Roi and clock at the board on my opponent’s time. Often the opponent has gotten up after making his move leaving the board vacant. I’ve never come back and found anything missing. There have been a few tournaments where clocks were vanishing when left unattended after a game was completed, or left in the skittles room. Occasionally I have handed my Mon Roi to the floor TD when I haven’t felt comfortable leaving it on the table.
Of course you can sit at the board looking at the position on the MonRoi screen which to some might be an advantage. It would be for me. I say that having used a recording program on my Palm Centro for informal games with friends.
I would agree with franc that the scoresheets should not leave the playing area. FIDE rules state that they must remain in view of the arbiter at all times, but I do not believe the USCF has something like this in the book.
I know more than a few players who have the habit of covering their scoresheet, usually with another blank scoresheet, uncovering only as much of it as is necessary to record moves.
Personally, if I’m working as a floor TD and someone tries to hand me his clock, set, MonRoi, coat, eyeglasses, false eye, etc. after his game ends, I will tell the player that I’m not the hat check person.
I know another TD who tells the player to put it on the table next to the sign that says “Free to a good home!”.
I notice that on occasion myself, although I cannot think of any actual benefit from this habit.
I think it’s mostly psychological. Trying to intimidate the opponent by making a big production out of hiding the scoresheet.
I often slide half of my score sheet under the board. There’s no psychological significance. It is merely a tactic to avoid having the score sheet fall onto the floor, where I can’t pick it up on my own. The problem is that I can’t lay the entire sheet flat on the table and still reach the top rows. Anyone who knows me is aware that I often show off my games–both good and bad. See my ICC library.
Michael Aigner
When I write my move before playing it, I’ll keep my hand covering the scoresheet, so my opponent doesn’t know what move I’m planning to play. This forces them to think about the response on their own time, not mine. But I also usually move within 5-10 seconds of writing down the move, unless my last second blunder check finds something, in which case I’m likely to cross off that move and play something different, anyway.
That is understandable. The psychological ploy I was referring to is when the opponent hides the score sheet even when writing down the opponent’s move, or just in general acts a little paranoid if he thinks the opponent is trying to look at it.
One possible benefit occurs when the first time control is approaching and you don’t want your opponent to be able to double-check the move count by looking at your scoresheet.
I’ve never bothered trying to hide my scoresheet.
Yeah, I know what you mean. I know one guy who asked to see his opponent’s scoresheet before the game started, just so he could copy the spelling of the opponent’s relatively unusual name, and the opponent refused. Some people are just jerks.