Sadly, laptop thefts occur in the library every quarter.
It may be really crowded, but the honest people studying around you are concentrating on their work not your laptop.
Don't be a victim of laptop theft.
Here is what you can do to protect yourself from laptop theft.
Record and store (somewhere other than your laptops) your laptop's serial number.
Mac:
Windows doesn't make this easy outside the command line. Best to just find it on the machine and write it down.