I've tried this with a hotel in Italy, and found out that the price was actually higher. I couldn't believe it. I actually asked the reception whether they were really sure. Yes, this is our price, they said.
I don't even if this is legal in your country, but in Germany they ruled against it: https://www.thelocal.de/20210518/germany-upholds-ban-on-book...
Many hotels are idiotic about this and will put a cheaper price on booking, then wonder why booking is taking all their reservations. Unexplainable...
> "Typically, additional costs for children (including extra beds/cots) are not included in the price. Please contact the property directly 1-2 days before your stay to find out more." https://www.booking.com/tpi_faq.html
After this, what's the point of using Booking.com?