If the purpose of a parking meter is to keep any one car from taking up that space beyond a short period of time (to allow access by many more people) then why would anyone allow you to extend the meter time remotely?
Case in point:
There was a homeless guy here in Raleigh that started a business dropping money in occupants parking meters just before they expired and leaving envelopes on their windshield stating that he had just saved them $25 and all he ask for in return was the 25 cents he put in the meter plus any gratuity they felt appropriate. WHAT A GREAT IDEA! He really raked in the cash up until they took him to court and raked HIM over the coals.
How DARE those homeless bums try to work their way out of a hole by making an honest buck helping people!!! Shame on them! It's darn a good thing we had our tax paid lawyers to kick them back into the streets where they belong!