Christmas and Halloween are no trademarks. You can use them and similar terms as you wish. Real trademarks like Microsoft can't be used. Trademark names like Apple are dependant from the context. If you show a green apple, you are allowed to use that, if you are using Apple and show a computer, it will get refused.
You will get suspended only for willfully violating the rules. Showing or using a tradename in your picture or using it in your title or keywords will earn you a refusal.
There are several things that will lead to suspension, however, like using copyrighted material or material where you do not own the property rights, like public domain photos. Because these are rules that are clearly enumerated in the terms and conditions. You can't argue using public domain files "by error".