Event Hub/Service bus publishing publically

Hi,

I know you can secure end to end messages in EH with SAS Tokens however is it suitable to expose Event Hubs publically without adding Layer 7 based security layers or Firewalls etc?

This is for a B2B type scenario.

Same question as well for Service Bus, i read it can also use API Management but i'd rather not add more cost/complexity if feasible.