Obviously you aren't too serious about this, and just wanted to get the agents on Trulia riled up.
In many ways, I agree with all the answers below, and I also know that, if you are serious, you will find flaws with every reason why we, as professionals, would not do this, so I'm not going to tell you why I wouldn't do this.
I will tell you why certain agents will do this, though. There are agents out there who are not that good in real estate, and as such, do not do much business. These are the agents that are literally working another job to be able to support their real estate "habit." These are also the agents who are unable to take any educational classes but the bare minimum, as they cannot afford those "extravagances."
So this is the type of agent that you will attract, one who isn't good at what they do, and can't afford to educate themselves to be good at what they do. So, that being said, I wish you the best of luck with your search, as this agent who will end up helping you may very well cost you a ton of money, by helping you to buy either an overpriced home, a home needing extensive repairs, or a home that will go down in value due to outside influences (new highway going in, or some sort of business that you don't want being built nearby, etc.) that any full-time, aware agent would already know about.
I wish you the best of luck in your search, and hope that you don't get in too much trouble in your purchase with the inexperienced, or bad, agent. I know that I can speak for everyone on here in saying that none of us need to work with someone who is obviously difficult, and that's because we have other clients who want to work with us, and not take away our income with inane requests. If you can't afford a home, please do not ask me to "help" you to afford it, using my money, that will be feeding my family.
Lastly, I would love to be a bug on the wall in an attorney's office when you ask him/her to cut his/her fees by 50% - the laughfest would be hilarious. Or when you ask the plumber to come in and stop the gushing leak, then, before he begins working on it, you ask him to cut his fees by 50% - it would be great to watch him, in his waders, watch your home flood. Or how about the firefighters, who, when told that you wanted to short your property taxes by 50%, thereby taking away much of their funding, watch your home burn to the ground.
Yes, I'm sarcastic, but the question you ask cuts to the bone. We work very hard to earn our money, and you have some gall to ask us to give some of it to you. Good luck in your search - we might be willing to give you some advice when you come back on this forum because your agent either doesn't have a clue as to what he/she is doing, or has failed miserably negotiating a home purchase for you.