Hovis told the Senate Budget and Taxation Committee that allowing questionable computer-run forms of electronic gambling could "threaten or harm the integrity of Washington County."
The county's tip-jar system distributes gaming revenues to fire and rescue companies and charities.
Hovis amended an earlier estimate he had given of the number of electronic tip-jar dispensing machines.
He said Wednesday the county had 26 of those machines, which are seen as an electronic equivalent of a person handing over preprinted tabs. Previously, he had put the number at about 15. Either way, he said, they represent a small percentage of the county's tip-jar system.
During three hours of testimony, committee members heard several distinctions of gaming described, particularly computer-generated numbers vs. preprinted tabs.
Supporters of the bill, including Senate President Thomas V. Mike Miller Jr. and Comptroller Peter Franchot, told the committee they want to rid the state of electronic gaming that appears to be outside of the law and might be avoiding proper tax accounting.
Opponents said the state is cutting into established, popular gaming that benefits needy groups by sharing revenues.
They also disputed what elements must be present for the games to be considered illegal.
Lobbyist Bruce Bereano, who represents an Arbutus, Md., gaming supplier that does business in several areas, including Washington County, spoke against the bill.
He argued that a form of electronic games his clients distribute, in which a predetermined set of numbers from a computer chip are printed on paper on the spot, would be protected by a Maryland court ruling.
But attorney Jason A. DeLoach of the firm Alexander & Cleaver said the ruling says that for a game to be legal, the chance has to depend on the ticket, not the machine. Blank paper, on which numbers are later printed, can't have an element of chance, he said.
Representatives from Allegany County, Md., which has about 30 of the same tip-jar dispensing machines as Washington County, also testified at the hearing.
The legality of another 140 electronic machines, which has a computer print numbers, hasn't been determined, according to Gerald Joy, the administrator of the county's gaming office.
Sen. Donald F. Munson, R-Washington, who is on the Budget and Taxation Committee, supports the bill, with the amendment that excludes the county's electronic dispensing machines.
Other members of Washington County's delegation are divided.
Del. John P. Donoghue, a Democrat, contends that the crackdown would protect the county's gaming interests.
But Del. Christopher B. Shank, a Republican, has said the bill is an attempt to protect the state lottery and possibly slot machines, which are up for a referendum vote in November, and could lead to further tip-jar regulations.