Probably, before cameras, royals could conceivably walk around in relative anonymity if they wanted to. Just take off your crown and you have an instant cloak of relative invisibility. I mean, we see Henry the V do it in that play. Here Hamlet can play dumb about basic Denmark facts and presumably the grave-maker is none the wiser.
How would he recognize a prince? By his portrait? Probably not in person. There not being much call for the overlapping of gravemakers and princes usually.
There are no photos, no videos – just paintings and drawings and engravings, which, no matter how artful, don’t necessarily make their way to the eyes of the people.
I think if I were a royal, I’d take great solace in being able to throw off my royalty for a moment and just wander as a human. I’d probably also have to be a male royal to make that really work, though – as ladies didn’t have quite the freedom of movement that I’d find optimal. Maybe, if I had been a queen, I’d have periodically dressed as a man to go out exploring.