As soon as you get settled and you walk out of your hotel for your first look around the town, you will be met by a polite, friendly young man who will give you a flower to welcome you. You're happy, he's happy.
The flower is a signal to several "priests" down the road, by the ghats, to detour you over to do puja...and charge you an exorbitant fee for the privilege. The presumption, apparently, and not too surprisingly, is that having just arrived you'll be disoriented and easier to deal with.
If you get into this predicament, don't get violent, don't raise your voice (it never helps to do this in India, and especially not at a holy city like Pushkar), but insist that you're not interested. You can also meet them at the temple...so just dont take any flowers of anybody in any place. The easiest way to get rid of them is to tell that you've alreday been in Pushkar and that you know their tricks!