The seller hires an agent and that agent has a duty to act in their clients best interest at all times. If you go to an open house the seller’s agent is required to post a sign indicating to Buyers that the agent is a SELLERS representative and DOES not represent the interest of Buyers for that open house.
If you want professional representation you should hire a BUYERS agent. This buyer’s agent will work in YOUR best interest and have a fiduciary responsibility to you. (Not the seller)
If you don’t want to work with a buyers agent You can still work with the Sellers agent BUT that agent would ALWAYS be acting in the Sellers’ best interest and NOT yours.

The situation of DUAL agency would only occur if you already had a contract with the agent doing the open house and PRIOR to the open house that agent was representing you and then you decided you wanted to buy that house. (this would be DISCLOSED DUAL AGENCY- and both buyer and seller must be informed in writing)

However since you are not under any contracts with this agent, it is clear that when you first met this agent that they represented the Interests of the Seller (Client) and you are only a Customer. Customers get a much different (lower) level of service?

You are free to Hire your own Buyers agent, HOWEVER be aware that the seller’s agent may not be obligated to pay your buyers agent since your buyers agent was not the procuring cause of the sale. (This is assuming that your agent is hired after you have already seen the house and your introduction to the property was as a result of the seller’s agents advertising)
So you may want to interview Buyers agent and tell them 100% of the story and see if they would be willing to work with you knowing that their compensation may be in dispute since they were likely not the procuring cause.

Most agents in this area know each other and if are upfront from the beginning can work out some type of deal so that you get FULL representation and both agents are compensated fairly.

Good Luck

They are required to disclose they are working for the seller but (sadly) more often then not they will just give you a piece of paper to sign tying you to them as a client instead of explaining in detail that what that paper discloses in that the agent works for the seller which means they are legally obligated to protect their interests NOT the buyers (you). So, don't sign any contracts without taking some serious time to read the fine print. You do, as a home buyer, have a choice to separate representation.

The only way you can be 100% certain your buyer interests will be protected throughout the home buying process is to work with an exclusive buyers agent - someone who never works with seller and also does not work for an agency that represents sellers.

Check us out here, not only do we work just with home buyers we also guarantee our client the lowest price on any home:
http://www.territoryre.com/howitworks.php

Eirinn....as a buyer you can choose whomever you want to represent you in buying the home. The seller's agent may represent both the buyer and the seller if both agree to dual agency. The seller has the right to instruct the agent not to practice dual agency. The sellers agent can represent you as a sellers agent, however, they have to disclose that to you. Just keep in mind, in that situation, the agent can tell everything to the seller, putting you at a disadvantage! It would be in your best interest to have a buyers agent representing you and your interest. Hope this helps. If I can be of further help to you please feel free to contact me @ jmansfield@weichertnewengland.com.