There are a lot of variables one has to consider before asking this question.
1. The age of the child.
2. Who they are collecting for, a tzedaka that you approve of and support.
3. Who organized the groups.
4. Who the driver will be
5. Where they are going
6. How you can contact him
7. When he will be home
Many yeshivos send their boys out collecting without any regard to the fact that the boys are mechuyav to have a seudah as well and should be at HOME for the seudah. They also rarely get involved and do not wish to be responsible for the arrangements including paying for the costumes.
When groups come to OUR home, before my hubby gives a check he asks to meet the driver and if he is a young driver we ask to see his license. We also make sure that the driver is not drinking and we offer coffee to him.
WE don’t appreciate bochurim coming in drunk to our home and they will not impress upon us to give them a check when they are that irresponsible. I have a table set up with cake, soda and coffee. If anyone asks us for mashkeh or even wine, we show them the door.
We also ask who the boys are and where they go to school.
It is hard to collect money in these hard economic times, and the job should not be left to young bochurim although we enjoy their enthusiasm and spirit.
So you really need to consider how old your son is, who he will be going with and were they will be going.