No conflict there. For SOAP stuff, an exception on 4xx/5xx is generally a sensible design. For human user-agents (ie, web browsers) there's still no conflict.

No conflict there. For SOAP stuff, an exception on 4xx/5xx is generally a sensible design. For human user-agents (ie, web browsers) there's still no conflict. Deciding whether or not to render some HTML is orthogonal to whether or not some other action might be taken. Generally, you do want to present a choice to the user at this point.