What is the largest event that has been processed on DT Register? Is it easily able to register 15,000 people for one event and process all of the information/payments? If so, is a dedicated, private server needed or recommended to do so? Same goes for how many multiple events could DT Register do at one time, an event of 15,000 plus 15 ongoing events of 300 people each?
This is more of a "can my server handle the load" rather than questioning DT register. It all depends on how many people are trying to connect to your site simultaneously...