_allow_level_without_connect_by parameters. Please need urgent help. Thank

Question

Hi,
We migrate a DB from 9i to 10g. Since we had the query bellow in 9i:
SELECT id, nvl(parent_id,0) parent_id,name , level
FROM sub_channels
WHERE parent_id = 1
and site_id = 1
and IS_HIDE_INTERNAL_TREE is null
ORDER BY name
It fails in 10g. I found the solution bellow, BUT I READ IT'S VERY RISKY AND COULD BE HARMFULLY, BUT I NEED AN EXPLANATION WHY TO MY BOSS :-(. CAN SOMEONE PLEASE ENLIGHT WHAT CAN BE RISKY AND HOW TO AVOID THE RISKS?
THANKS A LOT!!!!!!!!! Please see bellow what I found.
The LEVEL feature without connect_by should be use in 10g with the definition in the init.ora file as:
allowlevel_without_connect_by = true.
Because this is a dynamic parameter I can connect as SYS and change on the DB level the parameter value:
alter system set "_allow_level_without_connect_by" = true;
Now the default = false.

Answer 1

You still do not provide the link that says it is risky. See Metalink notes 271939.1 and 455953.1. They do not say setting that parameter is risky. What those notes say is using LEVEL without CONNECT BY is risky.
"If you are using level without connect by, it is highly likely that you are making a mistake that could lead to unexpected errors."
If you had tested your upgrade beforehand you would have seen this error and you would have tested if setting the parameter causes any risks.