Sounds like a good idea for a reality check. As you looking around and paying attention to your surroundings looking for your color, it increases awarenes also.

Only problem would be, as it would be with other RCs /dream sigh also, if you don't see this color/item in your dream. You will loose that chance to become lucid. That's why it's recommended to RC at random times, not tied to any particular situation or item.

But if you have a dram sign that's very frequent - let's say color, then it should work for you. And if this works for you, that's awesome. Happy dreams.