Comparison of null to Integer Always Returning true

I ran across an interesting phenomenon when comparing null values to Integer values on Visualforce pages: The comparison always returns true!

1. null < 0 evaluates to true
2. null = 0 evaluates to true
3. null > 0 evaluates to true

It appears that it's best not to compare null values to Integers, since the result is effectively useless.

Comparing Salesforce Record ID's in Visualforce

Strangely enough, the Visualforce comparison operator does not work when comparing a 15-digit record ID with an 18-digit one. The workaround I concocted is to use a very specific Boolean property in my controller extension to perform the comparison instead, since I really wanted to avoid using any kind of custom ID conversion code that may become invalid in future releases.

public Boolean isCitizenshipCountryUnitedStates {
   get {
       return stdCtrler.getRecord().get('Citizenship_Country__c') == unitedStatesCountryId;
   }
}

The situation I have is that I want to compare the Country of Citizenship specified on an application record (for custom object Application) to see whether the applicant is a U.S. citizen. Country of Citizenship is a Lookup(Country) field, with Country also being a custom object.

Without hardcoding the Id for the United States country, I defined a unitedStatesCountryId property as follows:

 public Id unitedStatesCountryId {
    get {
        if (unitedStatesCountryId == null) {
            List matchingCountries =
                    [SELECT Id FROM Country__c
                     WHERE Name = 'United States'];
        
            if (matchingCountries.size() > 0) {
                unitedStatesCountryId = matchingCountries.get(0).Id;
            }
        }
    
        return unitedStatesCountryId;
    }

    set;
}

When I evaluate the expression {!Application__c.Citizenship_Country__c = unitedStatesCountryId} in my Visualforce page, the expression always returns false. When digging a little deeper, I found that Application__c.Citizenship_Country__c was returning 'a0DT0000006NIDM' while unitedStatesCountryId was returning 'a0DT0000006NIDMMA4'! Visualforce appeared to be comparing the two values as Strings and not as Ids.

Finding no Visualforce-native solution, I had to go the route of creating the isCitizenshipCountryUnitedStates property in my controller extension. Needless to say, this quirk in Salesforce does not make me happy.