I'm very curious which languages most people asking about this question speak. In English, indeed, the phrase "(not) allowed" is completely ambiguous and context based! Maybe kind of tense-based as well -- present tense is usually about permission and policy, and past or future tense implies more of an active role.

"I don't allow my child to watch TV" - implies that I have a policy which forbids it, but the child might sometimes turn it on if I'm in the other room.

"I didn't allow him to watch TV that day" - implies that I was completely successful in preventing him from watching TV.

"I won't allow him to watch TV on the airplane" - implies that I plan to fully prevent it.

"My company doesn't allow any non-company-provided software to be installed on our company computers" - totally ambiguous. Could be a pure verbal policy with honor-system or just monitoring, or could be fully impossible to do.