The common risk is to be denied boarding altogether. You then get into a lot more trouble than it's worth. Also, if you lose your status you could struggle to get into the program again (that really depends on who's handling the case and which airline - it has been handled in the past in very different ways).

If you are really desperate, book on two separate airlines and use two credit cards - it's almost impossible to track (and for the real paranoid). There might be more info if you do a search.