Like any other street performers the goal of these clowns is to draw an audience and for that audience to give money. This is the source of the performers' income so they have a strong incentive to not only attract a big crowd, but also find methods to get this crowd to give them money.
While one may think the talent of the clown is the main driver of revenue I would have to respectfully disagree. Carefully thought out, and practiced techniques are the key to these clowns earnings.
Clowning Technique 1: A large line means there something good at the end.
At it's base, this technique operates using what is called "social proof". An example of a social proof would be "Well I don't know what I should do in this situation, but all those people are doing that, so I guess they know what they are doing...I'll copy them." If you see a large group of people around some clowns, you assume they must be pretty funny.
Clowns can manipulate the perceived size of the crowd by controlling the density. A widely dispersed group of 20 people doesn't seem as impressive as a tightly pack group of ten. If the clowns see their numbers dwindling they are quick to bring the crowd together, to give the illusion of a larger group.
Clowning Technique 2: Trap them
At the core of humanity is reciprocation. When a person helps another there is a silent, internal notion that the second party will help the original person in the future. When we are given things we often feel that we owe something back. This same dynamic is at play in clowning. These clowns give us a form of entertainment, and as we pay for other forms of entertainment like the movies, mini golf, etc., we feel the need to compensate them for their antics (and there is a small feeling of guilt if we do not).
This pressure becomes almost nonexistent when we stand in a large audience. We tell ourselves that all these people should pay too, but they won't so why should I? Unfortunately, the clowns know this and use it to their advantage.
When a clown walks up to a person brandishing their tip jar the clown separates her from the group. No longer can she blend in with the crowd. Suddenly all eyes are on her and heaven forbid she leave without paying and let their judgment fall on her. Leaving might be her best option because a refusal to pay will lead to some tauntings and public embarrassment by the clown.
Clowning Technique 3: Crowdfund
The final technique I'll cover in this post is an example of crowdfunding under duress.
If a clown wants to eat he cash do two things. Get a lot of money from a few people or get a little money from a lot of people.
After letting the audience ogle for a significant amount of time the clowns will stop their performance, raise their bucket up and cry out "Dias"! This is the call for ten pesos (a little less than a dollar). When the clown comes to a person with the bucket the last technique is invoked. Not only is everyone watching the poor victim, but they will definitely think him a cheapskate if he doesn't cough up the money. Worried that he will or face rejection from the pack he pays the ten pesos. Then the call goes back up "nueve pesos" (nine this time). Again a small amount. This process goes on until the clowns get to one and the show starts again. Each time the clown receives an amount, the next extortion becomes even easy. The closer to the required amount, the more pressure is placed on the victim, "it's already come this far, I don't want the crowd to blame the end of the act on me....."
And so the viewers leave with lighter pockets, and the clowns eat another day. This list is certainly not definitive, but I think with a little more viewing I can give an even brighter picture. One thing to note, I may paint the clowns in a negative picture in this piece, but they aren't evil (at least not in this scenario). Both parties entered into this social contract and any pressure either party feels is a part of that contact.