Suggestion for Booking.com
We have a couple of room types that are listed as double/twin rooms. There is an option on each room type for the guest to choose their preferred bed configuration (double or twin). More often than not the guest doesn't choose a bed type so we try and contact the guest to ask which they want.
About 50% of the time in this no-choice-made situations the guest is unreachable/doesn't answer the phone/respond to messages.
We then have to try and guess (!) which bed configuration they want. We're often wrong! This results in a bad guest experience. "We are a couple, we wanted a double bed!" or "We are colleagues we need separate beds!"
Please, please, please make the double/twin bed configuration choice mandatory. It will save us a lot of chasing the guest and give the guest a better experience - giving them the bed type they want.