Clarification on DateTime Format (1.7)

[an-ho]

Here is what Foundation-API section 1.7 says:

1.7 DateTime Format

DateTime values must be rfc3339 compliant.

Examples:
2016-04-28T16:31:12Z would represent Thursday, April 28th, 2016, 16:31:12 (0ms) in UTC timezone.
2016-04-28T16:31:12.270Z would represent Thursday, April 28th, 2016, 16:31:12 (270ms) in UTC timezone.
2016-04-28T16:31:12.270+02:00 would represent Thursday, April 28th, 2016, 16:31:12 (270ms) with a time zone offset of +2 hours relative to UTC.

And this is from BCF-XML 3.0:

DateTime Format

DateTime values in this specification are always of type xs:dateTime which is an ISO 8601 compatible YYYY-MM-DDThh:mm:ss format with optional time zone indicators. This is the same format as defined in the BCF-API specification.

For example, 2016-04-28T16:31:12.270+02:00 would represent Thursday, April 28th, 2016, 16:31:12 (270ms) with a time zone offset of +2 hours relative to UTC. Please note that the colon in the timezone offset is optional, so +02:00 is equivalent to +0200.

To void ambiguity, this specification steps away from ISO 8601 on the topic of DateTime values with no timezone: The ISO 8601 says that DateTime values with no timezone designator are local times - In BCF all DateTime values with no timezone designator are assumed to be in UTC.

So what about the brilliant part where you deliberately (and needlessly) violate ISO 8601?
Would BCF-API handle that differently than BCF-XML, or do the two behave consistently and you just forgot to mention it in the Foundation-API's documentation?