Aorist Verbs Vis-a-Vis Present Tense Verbs

Kendall H. Easley (User-Friendly Greek: A Common Sense Approach to the Greek New Testament, 36) offers an interesting example of how the aorist tense evidently works (in some contexts). He explains:

"What about the frequently stated idea that aorist verbs are punctiliar or point-of-time or once-for-all? This idea does not stand up. Consider this example.

ἐπορεύθη ὁ Ἰησοῦς τοῖς σάββασιν διὰ τῶν σπορίμων.

Jesus went through the grainfields on the Sabbath (Matt.12:1).

The action took up an extended period of time; in fact, the other Gospel writers use present tense forms to record this incident (Mark 2:23; Luke 6:1). Nor is there any hint that the action was completed so that it was once for all, never to be done again. In the aorist tense the action occurs, with no notion of its beginning, duration, or conclusion."

I've often wondered why Mark and Luke employ the present when describing this event instead of using the aorist. Any ideas?

Thanks,

Edgar