SQL Server Basic Availability group: one or zero listener for multiple AG

In my testing of SQL Server Basic Availiiblity Group, I successfully created AG1 for DB1 and AG2 for DB2 with only AG1 config’ed with listener IP. But when I use sqlcmd to test, I can connect to AG1’s listener and use AG2’s DB, do DDL and DML. Is it OK for this configuration? Only 1 listener for several AG.

Besides, I’m using pacemaker for cluster management, is it possible to config no listener for AG, just use pacemaker’s IP resource to bind IP on master server?