DEAR MISS MANNERS: My older sister and I are always getting into fights. She always wants something of mine and I always want something of hers.

We’ve tried trading, but it doesn’t work. This apartment isn’t big enough for both of us. What can I do?

GENTLE READER: Grow up?

No, Miss Manners realizes that you are looking for a shorter-term solution that does not involve hair-pulling.

Trading, as you have discovered, only opens up new areas for disagreement: Is a dinosaur worth two balloons or three? Unlike business transactions, family relationships involve gestures that are not immediately reciprocated. If your sister wants something of yours, you might try setting an example by simply letting her play with it or borrow it. If she doesn’t keel over from shock, she might, with quiet reminders, learn to reciprocate.

DEAR MISS MANNERS: If a family is getting together at Thanksgiving, and one of the families attending has a 2-year-old with egg and peanut allergies, does the mom have the right to email everyone and tell them they cannot bring anything with eggs and/or peanuts to the function?

I could understand it if the parents of the child were hosting the party, but if someone else is hosting and they are just attending, does that parent have the right to change everyone’s plans?

GENTLE READER: The “right”? Does that mean that you are asserting a counter-right to risk making a toddler dangerously ill?

Miss Manners is generally in favor of those with special requirements making accommodations for themselves without demanding them of others. But when the mere proximity of something poses a threat, it is polite, as well as humane, to comply.