It is true that most older laptops stored the BIOS password in the CMOS memory, which could be easily circumvented by disconnecting all power sources, removing the CMOS battery, and waiting 5-30 minutes. Most Pentium II's, and many Pentium III's were designed this way. However, I know of NO laptop newer than a Pentium III that can have a BIOS password reset in this manner.
All modern laptops store the BIOS password on an EEPROM on the motherboard. Depending on the manufacturer's policies, you may be able to get them to reset it if you are the owner, or you may have to go through the hassle and expense of changing out the motherboard, or attempting to unsolder the EEPROM and replace it. Since a laptop motherboard costs more than a new unit, very few people go this route.
Very few people who steal laptops are going to have the knowledge and skill to change out a motherboard, let alone to try and replace a chip on it. So at that point, the computer probably ends up in the garbage, or is stripped for parts.