Corner loading works at bass frequencies several feet away from the apex, so a port on the front of a corner-loaded speaker will act the same as one on the back unless the speaker is several feet deep.

When a sound source is placed at the apex of a trihedral corner, it radiates purely into eighth-space. The walls of the corner define the radiating angle. In this situation, the walls don't act as reflectors because a wavefront travels along them or away from them rather than towards them and reflected by them.

When a sound source is near a boundary, then it confines the radiating area and also acts as a reflector. At low frequencies, where the distance to the boundary is less than 1/4λ, the boundary constrains the radiating angle without any anomalies in frequency response. Above 1/4λ distance, the boundary begins to act as a reflector and peaks and dips will occur at 1/4λ multiples.

The end result of all this is that woofers and ports can be placed fairly far away from corners and still radiate into eighth-space.