Your banners are cooler cause they don't have the "trademark" sticking out... Mine does because I'm doing it from a website and do not want to pay to get rid of the trademark
and back on topic:
Ah so you mean encounter as in you just see it for a second? That should not be a problem then... You don't fight it or anything. And personally I'd suggest you actually fight the legendaries when they are under the control of the trainers, then only fight them when you can catch them.
Personally I don't mind NOT having all the legendaries, I love fighting other trainers who have legendaries because it is a challenge. They are not easy to beat no matter your level