Is watching an advertisement for gambling and games of chance forbidden (haram) or disliked (makruh)?

The scholars have forbidden watching reprehensible acts because it indicates approval of them. However, there is no harm in watching an advertisement about gambling and betting without people actually engaging in it, for the default rule regarding things is permissibility unless there is evidence of prohibition. This is unless watching it would lead to being influenced by it and pursuing it, or if it is highly probable that it would lead to that; in such a case, it is prohibited as a means of blocking the pretexts (sadd al-dhari'a).