The rule need to be reformed. I recently received awareness type message confirming sending of bulk message without registration is,a offence if found guilty liable to get disconnection and fine. The companies likely to monitor.numbers sending huge sms in future. So mind what you write and whom you send. One wrong move and you are out of network banned forever.
Companies already charging for sms 5 to 10 paise even you have a sms pack on while insider knew that operators hardly pay anything for sms.. This was once free within a sms pack. We now prefer web based sms instead paying for a monthly gprs pack is much better, as most of the phones are gprs enabled it is not a issue anymore.