The risks will always be there so all you can do is try and reduce them however you can. The main two ways I would suggest are as follows:
1) Save up as much as you can before starting any course. This will both reduce your loan repayments and will also give you more time before the repayments will start (as the 2 year period starts from your first drawdown)
2) Get on an MPL scheme. The main advantage being that if you successfully complete the course, it is likely that you will start work much sooner than with a CPL/IR and then having to wait to apply for jobs and complete a type rating.
Finally have a plan/job available that you could do immediately after training that will enable you to cover your loan repayments, in the event that you have a lengthy wait before getting a flying job offer.
As mentioned BBVA will expect the money to be paid on the repayments date, whether that is through an airline job or mcdonalds.