Miss Manners: Ask ‘us’ before declaring ‘dinner is on us’

DEAR MISS MANNERS: My friends, all gainfully employed adults, will often invite a group out to dinner or drinks to celebrate an occasion, like a birthday or professional milestone.
In some cases, it’s communicated that it will be a “no-host event,” with guests paying for themselves. If not, it’s understood that the host will treat the group.
Twice in recent months, when the check came, one of the guests has proclaimed that the group would treat the host. There is not much to be done in the moment without looking cheap or ungenerous, but I feel annoyed that one person has unilaterally made a decision for which I have to pay.
Is there anything to be done to avoid this scenario?
GENTLE READER: Your friends may be gainfully employed, but they are not what Miss Manners would call adults. Anyone who thinks they can get away with such behavior and still have friends has much maturing to do.
The immediate solution, if you do not feel like dropping such people entirely, is to decline invitations to “milestone” events — which seem to be increasing at an alarming rate.
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(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, [email protected]; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)