If you do a db.collection.insert(

) and
deserialize it from the Csharp driver you get an
InvalidOperationException: ReadInt32 cannot be called when BsonType is:
Int64. If I just enter a number javascript thinks it a float and I get a
similar error.

The Csharp drivers deserialization should be more forgiving. In the case of Int64 to int32, overflow should cause an exception to occur.
In the case of double to int32, an exception should be thrown if fractional parts are truncated.

Stack trace of the exception
at MongoDB.Bson.IO.BsonBinaryReader.VerifyBsonType(String methodName,
BsonType requiredBsonType) in D:\justin's
projects\mongo-csharp\Bson\IO\BsonBinaryReader.cs:line 587
at MongoDB.Bson.IO.BsonBinaryReader.ReadInt32() in D:\justin's
projects\mongo-csharp\Bson\IO\BsonBinaryReader.cs:line 283
at MongoDB.Bson.DefaultSerializer.Int32Serializer.Deserialize(BsonReader
bsonReader, Type nominalType) in D:\justin's
projects\mongo-csharp\Bson\DefaultSerializer\Serializers\BsonPrimitiveSeria lizers.cs:line
418
at
MongoDB.Bson.DefaultSerializer.BsonBaseSerializer.Deserialize(BsonReader
bsonReader, Type nominalType, Type actualType) in D:\justin's
projects\mongo-csharp\Bson\DefaultSerializer\Serializers\BsonBaseSerializer .cs:line
46
at
MongoDB.Bson.DefaultSerializer.BsonClassMapSerializer.DeserializeMember(Bso nReader
bsonReader, Object obj, BsonMemberMap memberMap) in D:\justin's
projects\mongo-csharp\Bson\DefaultSerializer\BsonClassMapSerializer.cs:line
221
at
MongoDB.Bson.DefaultSerializer.BsonClassMapSerializer.Deserialize(BsonReade r
bsonReader, Type nominalType, Type actualType) in D:\justin's
projects\mongo-csharp\Bson\DefaultSerializer\BsonClassMapSerializer.cs:line
95
at
MongoDB.Bson.DefaultSerializer.EnumerableSerializer`1.Deserialize(BsonReade r
bsonReader, Type nominalType) in D:\justin's
projects\mongo-csharp\Bson\DefaultSerializer\Serializers\CollectionGenericS erializers.cs:line
68
at
MongoDB.Bson.DefaultSerializer.BsonBaseSerializer.Deserialize(BsonReader
bsonReader, Type nominalType, Type actualType) in D:\justin's
projects\mongo-csharp\Bson\DefaultSerializer\Serializers\BsonBaseSerializer .cs:line
46
at
MongoDB.Bson.DefaultSerializer.BsonClassMapSerializer.DeserializeMember(Bso nReader
bsonReader, Object obj, BsonMemberMap memberMap) in D:\justin's
projects\mongo-csharp\Bson\DefaultSerializer\BsonClassMapSerializer.cs:line
221
at
MongoDB.Bson.DefaultSerializer.BsonClassMapSerializer.Deserialize(BsonReade r
bsonReader, Type nominalType, Type actualType) in D:\justin's
projects\mongo-csharp\Bson\DefaultSerializer\BsonClassMapSerializer.cs:line
95
at
MongoDB.Bson.DefaultSerializer.BsonClassMapSerializer.Deserialize(BsonReade r
bsonReader, Type nominalType) in D:\justin's
projects\mongo-csharp\Bson\DefaultSerializer\BsonClassMapSerializer.cs:line
63
at MongoDB.Bson.Serialization.BsonSerializer.Deserialize(BsonReader
bsonReader, Type nominalType) in D:\justin's
projects\mongo-csharp\Bson\Serialization\BsonSerializer.cs:line 76
at MongoDB.Bson.Serialization.BsonSerializer.Deserialize(Stream stream,
Type nominalType) in D:\justin's
projects\mongo-csharp\Bson\Serialization\BsonSerializer.cs:line 93
at MongoDB.Bson.Serialization.BsonSerializer.Deserialize(Byte[] bytes,
Type nominalType) in D:\justin's
projects\mongo-csharp\Bson\Serialization\BsonSerializer.cs:line 84
at MongoDB.Bson.Serialization.BsonSerializer.Deserialize[T](Byte[] bytes)
in D:\justin's
projects\mongo-csharp\Bson\Serialization\BsonSerializer.cs:line 58
at
Wunderman.EventRSVPSite.DataAccess.EventManager.GetEventLocations[T,t](Obje ctId
id) in D:\justin's
projects\LRT-MSC-O03023_EventRsvpSite\EventRSVPSite.DataAccess\EventManager .cs:line
109
at
Wunderman.EventRSVPSite.Service.RsvpService.GetEventLocations(GetEventReque st
request) in D:\justin's
projects\LRT-MSC-O03023_EventRsvpSite\EventRSVPSite.Service\RsvpService.cs: line
68
at SyncInvokeGetEventLocations(Object , Object[] , Object[] )
at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object
instance, Object[] inputs, Object[]& outputs)
at
System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(Message Rpc&
rpc)