I have played at Party, Empire, Stars, Paradise, and UB. They all have the same rule that a persons all in must raise atleast half the original bet or it doesnt count as a raise.

On an interesting side note, some B&M casinos let a player go all in at limit tables if their raise is 1.5X or less of what a regular raise would be. So at a $3-$6 table, someone could bet $6 and you could go all in for $9 more.