Alert and database log coexistence

While testing Database log functionality I found a tricky behaviour which can cause unwanted results.

Problem description
Alert is not generated, although Alert rule is enabled.

Steps
1. Create a new alert rule for Customers insert event
Accounts receivable > All customers > select Customer account field and right click > Create alert rule...

2. Add Customers table to Database log using a standard wizard
System administration > Setup > Database > Database log setup > New > Next > Open General ledger and select Customers

3. Create a new customer

4. Run Change based alerts job
System administration > Periodic > Alerts > Change based alerts

5. No alert is generated

Below you will find hints and solution description, however challenge yourself and try to repeat described steps and make assumptions :-)

Hints
Compare data in DatabaseLog table for CustTable before and after step 2.