First of all, this is a cautious attitude of enterprises towards talent selection. You seem to have done it for nothing, but enterprise training also needs manpower and energy.

Secondly, it is a clear violation of labor law for enterprises to do so. If it doesn't want you, you can collect work evidence, such as time cards and training notices, and ask the enterprise to pay labor remuneration. Of course, enterprises may also ask you for training fees, which is a very trivial matter.

Finally, the three-day enterprise training is not only to let the enterprise know about you, but also an opportunity for you to know about the enterprise. Why not? We say seeing is believing. It's a two-way choice anyway. Whether you want to do business or not, you should behave well for three days and observe carefully. If not, leave. Who can stop you?