Forbid developer to commit code because of making weekly build

Question

Our development team (about 40 developers) has a formal build every two weeks. We have a process that in the "build day", every developers are forbiden to commit code into SVN. I don't think this is a good idea because:

1. Build will take days (even weeks in bad time) to make and BVT.
2. People couldn't commit code as they will, they will not work.
3. People will commit all codes in a huge pack, so the common is hard to write.

I want know if your team has same policy, and if not how do you take this situation.

Thanks

Answer 1

1. Pick a revision.
2. Check out the code from that revision.
3. Build.
4. ???
5. Profit.