Unclear band order with GDAL S2 driver

Description

The band order when using the GDAL S2 driver without specifiying a subdataset explicitely is completely unclear, leading to user errors. For example:

otbcli_BandMath -il S2A_MSIL1C_20180620T040541_N0206_R047_T52XDK_20180620T083057.SAFE/MTD_MSIL1C.xml -exp "im1b1" -out im1b1.tif

outputs band B04 (i.e. the third band of the first subdataset).

gdal_translate for example, is more explicit and gives an error:

$ gdal_translate S2A_MSIL1C_20180620T040541_N0206_R047_T52XDK_20180620T083057.SAFE/MTD_MSIL1C.xml xml.tif
Input file contains subdatasets. Please, select one of them for reading.

Steps to reproduce

See above.

Configuration information

All.