The problem: You can't truly decide if you'd enjoy something unless you try it out. Unfortunately, this is currently not possible with live events that are paid, you either buy a ticket and attend or don't go at all. It would be cool if you could check an event for a short time, evaluate the quality of the performance, the general atmosphere, the people and then decide if you want to stay there.
The idea: A dedicated app that would freeze the deposit of a ticket price for a certain time. The staff would initiate the "short visit" process by scanning a barcode displayed on the phone's screen and deactivate it once you left the venue after checking out the event. The time for you to gaze around and leave the place could be 5-10 minutes. If you didn't manage to leave after that time and check yourself out at the door, the app would charge you the ticket price.
An alternative to charging the whole ticket price at once is to charge increasingly bigger sums as more and more time passes. You would be given a free of charge period of, let's say, 10 minutes, then after you breached that limit the app would charge you 1 euro, after 10 more minutes it would charge you 5, then 10, and finally the whole price (the whole price would be the sum of all the charged fees). The small amounts would be proportional to the full price of the ticket.
The latter seems like a better option because it gives a person more time to decide in exchange for a small fee and at the same time provides organizers with easy income, in case the person leaves, but once you paid something, even a small fee, it's way less likely for you to still leave after that and the likeliness decreases further with every additional fee charged. This would also eliminate the fear to be charged the full sum in case you are a bit late to leave.
Prevents waste of money for the customers in case they don't like the event.
Attracts more potential customers by eliminating the fear of going to something uncertain.
Check out a few events during the evening and choose one best to go to.
Organizers would likely invest more efforts in making a quality atmosphere of the event, to make those who check it out stay.
Possible disadvantages and solutions to them:
If many people would wish to check the event out this might create some mess inside the venue. It would be best to have a separate dedicated door for entry and exit of the short-time visitors. There would be two lines moving in the opposite directions (those who enter and those who exit) and two or more staff members scanning the barcodes. If possible, there could be a few doors through which you could exit and check yourself out, this would prevent "traffic" and loss of money due to being late for that reason. In bigger venues, the barcode scanning could be automated by using a scanner activating an automatic door/gate.
Having to check the short time visitors in and out would require some additional workforce for the venue, but the income gathered from those who fail to leave on time and those who decide to stay might be enough to justify this. In the worst case, the app could charge a small subscription fee from its users.