Exercise: Correction.

Outline: Use two images from your photo library, one with dust specs and one with lens flare. For the dust correction one, use the software's built in tools and for the lens flare one, use the clone stamp to correct the apparent blemishes. 

I searched through my photo library and couldn't really find any images with dust specs from the lens. I did, however, find an image from my library of assignment 3 images which had a lot of dust specs on the subject so I figured this would work just as well.

Although the dust specs are not from the lens, there are many visible in this image from dust on the surface and subject. The black background has a number of white specs, as does the nectarine. I used the spot healing brush in photoshop on as many of the white specs as I could and this had a dramatic result.

As you can see, the image appears a lot 'smoother'. All the specs have been 'corrected' and the healing brush has altered that spot to blend into the surrounding. This allows the subject to appear less flawed.
I attempted to correct this image using the clone stamp tool as well, but that was completely unsuccessful. I found that I had to be more careful to what I replaced the small spec with and it turned into a bit of a mess if i'm honest. The shadow and reflected area, along with the light reflection was difficult to alter getting the small area to match entirely to it's surrounding and I ended up with light bits where it should've been dark etc.

For the lens flare image, I have used a photo of a recent sunset. There is a very noticeable flare at the bottom of the image which, in my opinion, ruins the photo.

I followed the technique in the exercise, 'using the clone stamp tool  set to colour to integrate the flare polygons to their immediate surroundings and then set to darken with a close neighbourhood source', on the flare in the image. This wouldn't work with a spot healing brush due to the size of the flare and detail in the image.

This is the result and I can admit it looks great. The flare has been removed and is no longer the focus of the image, as in the previous version it took focus from the scene.

Conclusion:
I think that both correction techniques are quite innocent used in this manner. As stated the specs in the first  image were from dust on the scene but I still feel that removing them has bettered the image and is more a case of tidying the image than actually altering it.I feel the same about the lens flare too as this kind of alteration doesn't alter the appearance of the actual subject, only the flaws of the equipment/surroundings.
Depending on what the 'specs' you are removing/altering are could create a whole other argument though. As in the age old issue of retouching and airbrushing models in magazines. This is don't agree with as such because there you are actually altering how the model looks to create someone who, in fairness, doesn't actually look like that. And if they do that in a marketing campaign then you are falsifying the 'results' of the product, say for example make up, hair colourants, lawn products etc.