10 profiles in Belgium state yoni explicitly in their profile.
Do I need to agree yoni in advance?
Yes. Something appearing on a profile means it is open to discussion, not that it is automatically included in the rate. Mention it in your first message, and you will know straight away where you stand and how much time to allow.
Can a profile still refuse yoni?
Always. Everyone on the platform may say no at any moment, even if something is listed on the profile and even if payment has already been made. That is not an exception but the ground rule — not respecting it means a permanent ban.