Wow! You mean that they actually know you are the one still using the system and called you up. It is indeed impressive! 
It is very reassuring for parents like us to know that the online system is being carefully monitored in real time.
furui123:just want to share some experiences with the online registration system. initially i planned to do registration at school on day 3, but end of day 2 i called up the school and confirmed that the chance of getting in was quite high, so i last minute chose to do online registration. i login at 4.20pm, at 4.25pm i only managed to complete all the info but still need to wait for my husband to login via singpass. Then i received a phone call, it was from the school which i wanted to register. The school said MOE called them and informed them there was still a parent doing registration online, so school asked if i had any problems because the system would be close in 5 mins time and MOE couldn't close while someone were still using . i told them i was in the last step already and finished the registration just before 4.30pm. I have to say i am very impressed about how MOE monitor the system. i haven't submitted my registration (i think i used save button though) but they managed to or bothered to ask school to call parents!