op notes that hilton allows 2+ but marriott doesnt so this is usually a booking engine constraint or properties want to extract more $

op, book for 2 and email the property advising of kids... some have "kids under 12 free in existing bedding" some have fold out couch some will bring a crib with ir without fee some will offer upsell or free upgrade to larger room if occupancy is a problem..

i did quite a few one night stays in many different countries with kids without any contact in advance but we carried our air mattress and for longer stays i always emailed ahead

we need a master thread on this - seems to a weekly topic these days.. apparently fters were busy having kids over the last few years