No drinking?

I was waiting for the train this morning. Feeling a bit thirsty and knowing that I may faint if body lacks water, I took a sip from my bottle. It's plain water, not some sugar solution or juice. Yet 2 minutes later, a SBS TRansit staff came up and told me 'no drinking in the station'. I was a bit stunned but just nodded. You mean I can't take a sip of water at all in the station? I saw those 'No drinking' signs on the train but are they saying that if someone desperately needds water, they also can't drink even though it's plain water from their own bottle? I wonder if I will faint on the train ever again if I keep to their rule. Then again, I don't think I will follow what they want. It's ridiculous. Besides, I'm not dirtying the place, nor disturbing anyone.