Generally telephone sales of this type are illegal due to the telemarketing act however, often these telephone salespeople and group party planners will get the people's phone number from a party rental company, a wedding party consultants or someone like this.
This allows them to call up and solicit by the phone without breaking the law.
Generally telephone sales for group parties are a fairly easy job and many of the people that specialize in this type of sales make quite a bit of money.
A lot of times they will coordinate and get a very large commission with the caterer, DJ and other people who will be there to help out with the party.
Decoration specialists and the others mentioned usually come in a team.
One of the tactics of these telephone salespeople will use to sell group parties is to explain the deep discounting available for the number of people who are attending the party.
For instance for 10 to 20 people and maybe one price but for 30 to 40 people the price might be 30% less per person and they try to get the party bigger and bigger by asking the person they're selling to who else might they like to invite to their big party.
Please consider all this in 2006.