Thanks for that post — that&#x27;s interesting, and explains a considerable bit. I ride CalTrain often, but their readers are bolted to the concrete… I&#x27;m surprised they&#x27;re not updated more frequently? (Even the CalTrain operators say to give a week.)<p>The whole &quot;tag on&#x2F;off once at the beginning of the month&quot; (which I&#x27;ve always thought was the weirdest thing…) then is to sync the on-card value w&#x2F; what you own I suppose, so that it scans properly on their readers. Now I wonder that given that I buy from Walgreens, if that&#x27;s an absolute necessity, or a hardship imposed by people being too lazy to explain the inner workings of the card; it&#x27;s a pain b&#x2F;c if you forget to tag off, you get charged full-fare (<i>and</i> your monthly pass is deactivated until you re-add value to the card…), as I&#x27;d much rather just buy the monthly pass and not have to do the monthly tag dance.