[pdappollonio]

I provided consulting for a mobile carrier before. The reason why this doesn't happen is because once you do apply data caps, users often try to "not eat their entire allocation the first day" because otherwise they would lose internet halfway through the month.

The same reason as to why you don't use your entire paycheque at the beginning of each month when it drops.

Granted though, in terms of internet, this is not a detriment (at least not enough) to think you won't have internet by the end of the month. But that'd the thinking behind caps, that people would even out their usage through the month.