If you're interested in the requirements imposed on the sponsors you can look through them them on NAFSA site. If you look at some of the requirements imposed on the sponsor the company of 30 employees it would be cost prohibitive because for example:
§ 62.8 General program requirements.
(a) Size of program. Sponsors, other than Federal government agencies, shall have no less than five exchange visitors per calendar year. The Department of State may in its discretion and for good cause shown reduce this requirement.
(b) Minimum duration of program. Sponsors, other than federal government agencies, shall provide each exchange visitor, except short-term scholars, with a minimum period of participation in the United States of three weeks.
(c) Reciprocity. In the conduct of their exchange programs, sponsors shall make a good faith effort to achieve the fullest possible reciprocity in the exchange of persons.
(d) Cross-cultural activities. Sponsors shall:
(1) Offer or make available to exchange visitors a variety or appropriate cross-cultural activities. The extent and types of the cross-cultural activities shall be determined by the needs and interests of the particular category of exchange visitor. Sponsors will be responsible to determine the appropriate type and number of cross-cultural programs for their exchange visitors. The Department of State encourages sponsors to give their exchange visitors the broadest exposure to American society, culture and institutions; and
(2) Encourage exchange visitors to voluntarily participate in activities which are for the purpose of sharing the language, culture, or history of their home country with Americans, provided such activities do not delay the completion of the exchange visitors' programs.
And the list of requirements go on. So while the legal aspect can probably be handled by an ouside law firm some of the program requirements have to be handled in house and to be able to select and handle at least 5 visitors a year may require 1 or 2 full time staff. So doing that is usually furthest thing from the mind of such a company's management.