I must admit I thought deducting some time (using the arbiter's best judgement) from the clock of a player who is unable to keep score was just common practice, widely used for example in cases with religiously observant people who feel they're not allowed to write on the sabbath, or with children who haven't yet learned chess notation.
The section quoted by TalJechin from 8.1.e in the FIDE laws seems to support this:
Quote:If a player is unable to keep score, an assistant, who must be acceptable to the arbiter, may be provided by the player to write the moves. His clock shall be adjusted by the arbiter in an equitable way.
Note that a) the player is assumed to be
unable to keep score, and b) an assistant
may be provided, not
should be provided. The rules here appear to acknowledge the possibility of the (probably not infrequent) situation where no assistant is on hand and the result is that only one player is recording the moves.
If the arbiter accepts that a player is unable to record the moves in the first place, it's only fair that s/he gets a 15-minute deduction, or whatever seems appropriate to the time control.
Actually, in the newest revision to the FIDE laws, 8.1.e continues
Quote:This adjustment of the clock shall not apply to the clock of a player with a disability.
So a more assertive (or obnoxious, depending on perspective) opponent could have claimed to be effectively disabled without his glasses and demanded no time deduction whatsoever!