Helrow?? people needing cash for the weekend is NOT much of any reason for what seems to be a tendency for weekend dumps, it's NOT even a very plausible reason.

A few of the more plausible reasons for weekend dumps are: 1) it remains waaaaaay easier (cheaper and without time barriers) to move BTC than fiat (especially over the weekend), 2) a large number of people have some skepticism about keeping fiat on exchanges, and therefore when downward price pressures (selling of BTC) come, there is NOT enough money on exchanges to stop such downward price pressures, 3) some people are NOT paying as much attention over the weekend because they are engaged in other activities (such as recreation etc) allowing manipulators to push BTC price down by selling when buyers are occupied, and 4) another reason could be fear to hold BTC when many people can fairly confidently predict based on the trend a bit of a downward price movement over the weekend.. which may cause some additional sales from some of these people attempting to time such apparently likely downward price movement (to try to make a few bucks)