Wow. Matamoros is right next to South Padre.
We used to go to South Padre several times a year and walk across the bridge to Mexico, spend most of the day going to the new market and the old market and then back to South Padre. Even walked back from the new market to the bridge crossing on occasion.
On our last trip, eight years ago, noticed that the entire bridge was lined with beggars, not as much merchandise was available and we felt some uneasy by the stares of the men so decided we wouldn’t go back. Really too bad - it was a fun place to go and South Padre Island was a great place to take the family.