Oh yeah, They will email you back.

Besides the price look for:

Most of the time, The seller is not local.  The trailer is here and he is overseas and needs to see it despartly at any price.

Most of the time, The seller is really not very knowledgeable about his trailer. You can ask questions like, "I see this is a Hart Trailer, they come with doube wishbone axles, How have you liked those axles?"  the seller will gush about how great double wishbone axles are. The point being is they don't own the trailer they are selling, and hence will not have a very good knowledge of their trailer.  Most owners who spent tens of thousands on a trailer, usually know what features it really has.

Most scams are put up by foreign nationals. Hence their use of the english language is poor. Watch for poor grammer in their descriptions of the trailer.

This does not mean that a local dirtbag will attempt the same scam.