Yes, It is not offensive. It means the person is doing it excessively so it is not a compliment either, but probably just like “to tag along”.

Note that basques meaning is mostly forgotten nowadays. This word only survives in the figurative set expressions coller/accrocher/pendu aux basques.

A similar expression is coller aux pattes (stick to the legs).

Basques is unrelated to the Pays Basque but is an old name for some pieces of garment hanging downward from the waist.

“Accroché à tes basques” is a very informal wording that expresses a bit of mockery, but it is not necessarily offensive nor condescending. In that context I would interpret it as a little teasing which is not incompatible with affection.

This connotation is not conveyed in the English “tag along”, which sounds to me very neutral.

You are right when you say that it really depends on the context: if you complain and tell to somebody “Arrête de me coller aux basques”, then it is clearly a negative statement and the person you’re speaking to would most probably be offended. It could also be condescending, as this way of reproaching someone for following you may understate that they are just some kind of weight.