Apologies for the grotesque nature of this example. I was too appalled to find such an error in a major newspaper to realize how offensive the subject matter was--
The body was found beneath a pile of bedsheets in an advanced state of decay, the court heard, inside a bedroom full of house flies that had also been sealed with tape.
What was sealed with tape? The house flies? No. The bedroom!
Dangling modifiers can be sneaky. Here's one that is a whole clause (that had been....) which has been misplaced. Relative clauses (that/which and verb-- relative clauses are adjectival usually, that is, they explain or amplify a noun) are easily misplaced. They should be adjacent to the noun they modify, and not adjacent to any other noun.
I think we need to train ourselves to "listen" for mistakes like this.
I'm not sure how to fix that sentence. How would you revise it to get rid of that dangler?