To me romantic implies a relationship that is familiar.
In the initial stages of my relationships, while familiarity is building, I try to be as natural as I can be without the push of romance. I am romantic at heart so sometimes me being me is seen or accepted as romantic.

At the point where the relationship builds to love. I have been known to be a grand romantic because I demonstrate my love when I feel it. The deeper the love I feel the more grand the gestures I use to express it.

To me a grand romantic gesture is not one that requires money, work or sacrifice. Grand represents a gesture that specifically demonstrates my love to her. Since I tend to love whole-heartedly I put everything I can muster into making her feel my love for her.

If I have not realized love for her and she demonstrates a grand romantic gesture towards me I understand and accept her act of love as long as I can see a relationship as being possible. If I do not see us in a relationship of more than friendship then I will stop her and thank her and explain how I feel.

Any romantic gesture, grand or not, that is directed towards me when there is no relationship I just ignore unless I feel some connection might be possible. Its like sexual advances from strangers in a bar. If I am not interested I ignore.

What makes any gesture romantic is how well you know and care for each other. The gesture is personal and meaningful. You can give someone a single rose and it might be ho-hum or it might make her cry tears of joy.