Question regarding mortgage refinance

Since we bought our house, my mortgage agent called us regularlly once a year to refinance on lower rate. By the way, our loan is 30 years fixed. The agent asked me to pre sign application form and provide supporting materials such as pay slip, bank statements and the agent will keep them so that the agent can lock the rate when is low.

We did a few times, but is getting increasingly uncomforable after hearing too many mortgage fruads. Since we do not anything behind the mortgage finanace, we would like to know if there is any risk or pros/cons to follow the agent’s suggestion and refinance every year.

Thanks in advance