Especially when there are boobies involved:

Boaters -- nude ones and those wearing bathing suits -- have attracted the attention of drivers in recent weeks, at times halting traffic at the causeway between Iredell and Mecklenburg [North Carolina] counties and sparking complaints.

Two items seem to have caused the "sudden" appearance of "nekkid people":

[Marine commission Chairman Randy Reece] suggested the problem was created inadvertently when the N.C. Department of Transportation took down the causeway fence and started trimming the weeds and underbrush that once obscured views of the lake.
...
The [Marine] commission approved a new rafting safety ordinance last month after lakefront homeowners complained about the massive floating party in Cocktail Cove. Residents reported nudity, drunkenness and obnoxious behavior.

The new rules limit the number of boats that can raft together at certain distances from shore. They apply lakewide.

Which is why they're hanging out at the bridge now. Heh... see, sometimes even bad government can be good. Well, until some young thing gets you in an accident I guess.