If you read the RV-10 forums, you will find that this is a sensitive issue. There have been a large number of doors lost in flight... at least considering the size of the RV-10 fleet. The factory initially developed a door indicator light and more recently designed a redundant safety latch. The factory solution is simple, yet sore on the eyes. Other folks have developed a variety of solutions that you might want to consider.
Many pilots refuse to modify their airplane and insist the door cannot open if properly latched. This is technically true... but this approach depends on an infallible pilot. I personally prefer a safety latch but, legally speaking you are free to do whatever you wish.