The Imperial Family of the Great Xia dynasty had strict rules for members undergoing training outside the palace.
The performance and achievements during this training even determined the cultivation resources one enjoyed later within the Imperial Family.
Among these rules, one stated that before reaching the specified time of training, any contact with one's royal kin was forbidden.
Otherwise, if you were bullied today and cried to your mother, she might soften her heart and send a few experts to protect you.
Tomorrow, if you encountered some difficulties, you might contact a royal uncle or someone to help you solve the problem.
That would defeat the whole purpose of training outside.
Even if Xia Yunzhao was a once-in-a-millennium genius, it wouldn't be good to violate the rules set by Emperor Min.
As for why she could ask Li Mi for help when in danger, it was because of the Seventh Princess's personal connections.