Currently, my kid is 114cm tall and we are riding train this April

Will they measure my young kids again before we board the train as <120cm is free? We will only be buying the tickets for adults and taller kids in advance. I measured kid at home with flip flops on but their tennis shoe will add another 2-3cm to their height. I'm afraid if we show up at the train station and my kids grows another 2-3cm by then, we'll risk possibly not having a seat or space on the train if it happens that the train is sold out in April. Hope they don't get out ruler and measure kids height too strictly.