This touches on one of those OGC permathreads, which could be summarized as "why should I
worry about the CRS definition - if I don't say anything then everyone will know it is lon-lat WGS
84 won't they" to which the answer is, unfortunately, "no". There are distinct
traditions in different sub-sectors of our world where the sub-community actually makes different
assumptions from other sub-communities. For example, the good-old cartographers tradition is
lat-lon (i.e. northing before easting) with numbers in sexadecimal + hemisphere (DMSH). A commonly
used map projection in South Africa is based on southing and westing. And most data in Australia is
still given using a datum which offsets everything 200m from WGS84. Unfortunately, the only safe
way is the explicit way. This includes not only datum and projection parameters, but also axis
order, axis direction, and possibly encoding.
Simon