Unfortunately, the service has a major flaw.
The registration requires the user the input their go card account number and password details. Only an idiot would give out their username and password to a third party, as the third party can then access that account carte blanche. It also happens to be clearly in breach of TransLink's terms and conditions. Naughty, naughty! Thus, BrizCommuter does not recommend using this service.
This idea does beg the question - should TransLink do this themselves? Given the huge amount of unclaimed go card fixed fares (and thus added income), it is not unreasonable to expect TransLink to be able to afford a text message service to the customers registered mobile phone number if they receive a fixed fare. TransLink not clearly informing customers of financial penalties made by their faulty equipment could even be argued as being fraud. It is not difficult to automate a SMS text message service, and this is something that is commonly performed for hospital appointment reminders for example. However, as with anything from TransLink, don't hold your breath.