Actually you are getting the error code 4301: "Database in use ... " if you
are
trying to load a transaction file, while users are connected to the
database.

But if the database would be in readonly mode it would be great to have
still
the possibility to load the transactions as a warmstandby load.

Why?

With this option it would be possible to have readonly operations on the
database.
This database mostly would the backup database which could also
be used for selections.

This feature would be very usefull as a simple replication mechanism without
a replication server.