As I work on a series of tables regarding unaccounted for character abilities, I find myself stumped by a peculiar condition of role-playing games - the 'negative result' ... this being any circumstance where the character suffers a penalty towards any circumstance. This might be a modifier to attack or damage, or a penalty on their saving throw, high subsceptibility to cold, an intolerance to alcohol ... anything a DM might care to instigate as part of a player's character.
One thing you can be sure of, if a character has a bonus modifier in a saving throw, they will not hesitate to point it out at every opportunity. The DM need not 'keep track' of such a modifier. But if the player has had an accident, or some genetic trait long ago determined that the character is subsceptible to, say, something uncommon like fish poison (-1 save against), you can bet the character will 'forget' that modifier six months later when stepping on a stone fish. It may be that the character has actually forgotten - DMs regularly construct tables which get infrequent or profoundly infrequent use ... and players don't concentrate on remembering things that could someday hurt their character. Chances are when the day comes that the character does step on a stone fish, the modifier will never be applied.
That is because responsibility for the negative aspects of a player's character invariably fall upon the DM ... no player wants to advance information that might potentially kill their character. And like I say, it is in the player's interest to shove that information right out of their mind - that's human nature. You might have a player digging through their character sheets and shouting, "I have a +1 attack against left-handed goat-headed transvestites who worship Lloth!" ... but you will NEVER have a character rummaging through their sheets to admit they suffer twice normal damage from falls due to the liver disease they contracted last year.
Problem is, obviously, DMs can't rationally keep track of this information either ... there's just too much of it. Even if the DM has written a note, "Carack, -1 save vs. fish poison," the chances are this note will not see the light of day the evening the saving throw occurs. The DM might run across the note in advance, and intentionally place the stone fish into the encounter so as to say at the appropriate moment, "AHA! -1 save!" ... but if the fish happens to be a random encounter, forget it.
What usually happens is that three months after the DM is stuck saying, "You remember when you made that save vs. the stone fish? Well, it was supposed to be at -1. C'est la vie." Although I have known DMs to argue that a minute amount of the poison has been working its way through the character's system all this time, and another save is required, this time at -10. "C'est le morte."
And that is one possible solution - ten times the effects of any negative modifier a character forgets, but is later remembered or identified by the DM. More likely, however, is that the modifier will never be remembered.
The default position then in most campaigns is to never supply the character with a negative modifier for anything. For those DMs out there who consistently slag and spit upon any attempt at simulation, this makes sense. For me personally it's a wallbanger, since without conflict to overcome, what we have is a game comprising of boring, predictable sludge, suitable for children but no one for whom sophistication is the meat of gaming.
Yes, it is a major bitch that my character's constitution is so low that eight hours of marching leaves him so weak that he can no longer lift his quarterstaff, much less gather together the magical forces necessary to sweep his enemies aside - but I want my weakness, I want to have it to bitch about, to torture the other party members with, to insist again that we have got to stop and rest because my feet hurt! I'm not interested in running a perfect being. Powers are not the whole game - flaws must count at equal value!
At this point I feel myself drifting into a rant about non-simulationist gaming, so I'll resist and desist. It's time for me to go download some porn (where flaws truly don't belong). I confess, I have no solution to force players to remember their negatives. I only hope they do.