Only assigning valid customer when changing customer ?

[Otabutin]

Hello,

I notice in the Service Desk 3.0 version that it is possible to fill any customerID when changing of customer on the ticket via the link 'Customer'.
Which could be dangerous, as the ticket may be reassigned to a NULL customer or to a customer not existing.
Is there an option displaying a kind of selection list there or allowing a validation of the ID filled at change ?

Thanks for your help.