I do think its a bit strange but it depends on your plans, I know a few people that have run off and done it quickly with no guests just a simple cheap option ceremony and people who have had a ceremony then just a meal in a pub/resteraunt/hotel before to keep costs down but no one that had a ceremony with guests that just stopped abruptly.
I understand your reasoning for wanting to save money but reception's dont HAVE to be expensive, some places round here do reception packages for £500 (including hire, decor, food, dj, wedding planner etc...) and the couple dont really have to do anything except pick a colour scheme but even if that seems too much or not personal enough there are cheaper options such as garden parties. picnic in the park and bbqs.
doing something like a bbq or picnic could keep costs really low and allow families to mingle and celebrate, they dont have to last all night like conventional parties and could instead last maybe 2 hours as they are usually outdoors and open to the eliments and a picturesq park could make a beautiful beackdrop to get the most out of your photographer without having to splash out for full day coverage.
there are also some nice venues that offer free room hire or room hire for a refundable deposit if you can find them, you could instead invite people to mingle at a casual cocktail party. you could have a cash bar (usually the reason room hire if free) and then just put on some small snacks or canapes and maybe get a cake to cut (asda do wedding cakes from £35) all in all it could be done for under £100 as the guest would buy their own drinks, you could leave at anytime if you dont want a long reception and it gives guest that want to celebrate the opitunity of somewhere to stay and drink together in one place.
as a guest I probably wouldnt be able to justify just going to a ceremony alone, especially if it involved travel or time off work (like many do) on top of outfits and gifts.
however if you only want a small wedding with immediate family who you know will come regardless then you could just explain it to them though, and maybe see if theres any affordable pubs/buffets/resteraunts in the area and go for a close family meal to celebrate afterwards.